Fix coverage.xml path to use absolute path

The coverage.xml file wasn't being generated in the expected location, causing the coverage extraction to fail and report 0%. Using github.workspace ensures the file is written to the correct location.

Author: aristath

.github/workflows/code-coverage.yml

@@ -65,7 +65,7 @@ jobs:
 
       - name: Generate code coverage report for current branch
         run: |
-          composer test -- --coverage-clover=coverage.xml --coverage-text | tee coverage-output.txt
+          composer test -- --coverage-clover=${{ github.workspace }}/coverage.xml --coverage-text | tee coverage-output.txt
         continue-on-error: false
 
       - name: Upload coverage to Codecov