DEP: Bump actions/upload-artifact from 4 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -44,7 +44,7 @@ jobs:
         shell: cmd
 
       - name: Upload Artifact / Plugin
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         if: ${{ success() }}
         with:
           name: WiFiRemote
@@ -139,7 +139,7 @@ jobs:
         shell: cmd
 
       - name: Upload Artifact / MPE1
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         if: ${{ success() }}
         with:
           name: WiFiRemote MPE1
@@ -149,7 +149,7 @@ jobs:
           if-no-files-found: error
 
       - name: Upload Artifact / MPE XML
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         if: ${{ success() && needs.changes.outputs.changes == 'true' }}
         with:
           name: WiFiRemote XML
@@ -181,7 +181,7 @@ jobs:
         shell: cmd
 
       - name: Upload Artifact / Version Description
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         if: ${{ success() && needs.changes.outputs.changes == 'true' }}
         with:
           name: WiFiRemote Version Description