chore: reduce unnecessary package exports (#148)

## This PR
Fix broken symlink artefact.

Updates package exports to reduce clutter.


### Notes
Prompted by a broken deployment, which was trying to chown files in an
entrypoint and falling over with `.pre-commit-config.yaml` (which links
to a non-existent file), causing the container to crash.

It may be easier to read the PR by disabling the whitespace in the diff,
as I had to realign the existing spacing.


### How to test
Checkout this branch, then `git archive HEAD | tar tf -`.

You should receive the following:
```text
LICENSE
README.md
composer.json
src/
src/OpenFeatureAPI.php
src/OpenFeatureClient.php
src/implementation/
src/implementation/.gitkeep
src/implementation/common/
src/implementation/common/ArrayHelper.php
src/implementation/common/Metadata.php
src/implementation/common/StringHelper.php
src/implementation/common/ValueTypeValidator.php
src/implementation/errors/
src/implementation/errors/FlagValueTypeError.php
src/implementation/errors/InvalidResolutionValueError.php
src/implementation/flags/
src/implementation/flags/Attributes.php
src/implementation/flags/AttributesMerger.php
src/implementation/flags/EvaluationContext.php
src/implementation/flags/EvaluationContextMerger.php
src/implementation/flags/EvaluationDetails.php
src/implementation/flags/EvaluationDetailsBuilder.php
src/implementation/flags/EvaluationDetailsFactory.php
src/implementation/flags/EvaluationOptions.php
src/implementation/flags/MutableAttributes.php
src/implementation/flags/MutableEvaluationContext.php
src/implementation/flags/NoOpClient.php
src/implementation/hooks/
src/implementation/hooks/AbstractHook.php
src/implementation/hooks/AbstractHookContext.php
src/implementation/hooks/BooleanHook.php
src/implementation/hooks/FloatHook.php
src/implementation/hooks/HookContextBuilder.php
src/implementation/hooks/HookContextFactory.php
src/implementation/hooks/HookContextTransformer.php
src/implementation/hooks/HookExecutor.php
src/implementation/hooks/HookHints.php
src/implementation/hooks/ImmutableHookContext.php
src/implementation/hooks/IntegerHook.php
src/implementation/hooks/MutableHookContext.php
src/implementation/hooks/ObjectHook.php
src/implementation/hooks/StringHook.php
src/implementation/provider/
src/implementation/provider/AbstractProvider.php
src/implementation/provider/NoOpProvider.php
src/implementation/provider/Reason.php
src/implementation/provider/ResolutionDetails.php
src/implementation/provider/ResolutionDetailsBuilder.php
src/implementation/provider/ResolutionDetailsFactory.php
src/implementation/provider/ResolutionError.php
src/interfaces/
src/interfaces/common/
src/interfaces/common/LoggerAwareTrait.php
src/interfaces/common/Metadata.php
src/interfaces/common/MetadataGetter.php
src/interfaces/common/StringIndexed.php
src/interfaces/common/TypeValuePair.php
src/interfaces/flags/
src/interfaces/flags/API.php
src/interfaces/flags/AttributeByTypeExporter.php
src/interfaces/flags/AttributeType.php
src/interfaces/flags/Attributes.php
src/interfaces/flags/Client.php
src/interfaces/flags/EvaluationContext.php
src/interfaces/flags/EvaluationContextAware.php
src/interfaces/flags/EvaluationDetails.php
src/interfaces/flags/EvaluationOptions.php
src/interfaces/flags/FeatureDetails.php
src/interfaces/flags/FeatureValues.php
src/interfaces/flags/FlagValueType.php
src/interfaces/flags/MutableAttributes.php
src/interfaces/flags/MutableEvaluationContext.php
src/interfaces/hooks/
src/interfaces/hooks/Hook.php
src/interfaces/hooks/HookContext.php
src/interfaces/hooks/HookHints.php
src/interfaces/hooks/HooksAdder.php
src/interfaces/hooks/HooksAware.php
src/interfaces/hooks/HooksAwareTrait.php
src/interfaces/hooks/HooksGetter.php
src/interfaces/hooks/HooksSetter.php
src/interfaces/hooks/MutableHookContext.php
src/interfaces/provider/
src/interfaces/provider/ErrorCode.php
src/interfaces/provider/Provider.php
src/interfaces/provider/ProviderAware.php
src/interfaces/provider/Reason.php
src/interfaces/provider/ResolutionDetails.php
src/interfaces/provider/ResolutionError.php
src/interfaces/provider/ThrowableWithResolutionError.php
```

Signed-off-by: Chris Lightfoot-Wild <[email protected]>

Author: ChrisLightfootWild

.gitattributes

@@ -1,23 +1,32 @@
-/.editorconfig              export-ignore
-/.gitattributes             export-ignore
-/.github/                   export-ignore
-/.gitignore                 export-ignore
-/.readthedocs.yml           export-ignore
-/build/                     export-ignore
-/captainhook.json           export-ignore
-/CHANGELOG.md               export-ignore
-/codecov.yml                export-ignore
-/CODE_OF_CONDUCT.md         export-ignore
-/CONTRIBUTING.md            export-ignore
-/conventional-commits.json  export-ignore
-/docs/                      export-ignore
-/phpcs.xml.dist             export-ignore
-/phpstan.neon.dist          export-ignore
-/phpunit.xml.dist           export-ignore
-/psalm-baseline.xml         export-ignore
-/psalm.xml                  export-ignore
-/SECURITY.md                export-ignore
-/tests/                     export-ignore
+/.editorconfig                 export-ignore
+/.gitattributes                export-ignore
+/.github/                      export-ignore
+/.gitignore                    export-ignore
+/.gitmodules                   export-ignore
+/.pre-commit-config.yaml       export-ignore
+/.readthedocs.yml              export-ignore
+/.release-please-manifest.json export-ignore
+/.tool-versions                export-ignore
+/build/                        export-ignore
+/captainhook.json              export-ignore
+/CHANGELOG.md                  export-ignore
+/CODEOWNERS                    export-ignore
+/codecov.yml                   export-ignore
+/CODE_OF_CONDUCT.md            export-ignore
+/CONTRIBUTING.md               export-ignore
+/conventional-commits.json     export-ignore
+/devenv.*                      export-ignore
+/docs/                         export-ignore
+/integration/                  export-ignore
+/phpcs.xml.dist                export-ignore
+/phpstan.neon.dist             export-ignore
+/phpunit.xml.dist              export-ignore
+/psalm-baseline.xml            export-ignore
+/psalm.xml                     export-ignore
+/release-please-config.json    export-ignore
+/renovate.json                 export-ignore
+/SECURITY.md                   export-ignore
+/tests/                        export-ignore
 
 *                           text=auto
 *.bat                       text eol=crlf