ci: use codecov token when uploading reports (open-telemetry#2468)

Author: pichlermarc

.github/workflows/unit-test.yml

@@ -139,6 +139,8 @@ jobs:
       - name: Report Coverage
         if: ${{ matrix.code-coverage && !cancelled()}}
         uses: codecov/codecov-action@v4
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
           verbose: true
 
@@ -170,5 +172,7 @@ jobs:
         run: npm run test:browser
       - name: Report Coverage
         uses: codecov/codecov-action@v4
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
           verbose: true