Allow failure of "Report coverage" step in "run_tests" job (#9073)

Co-authored-by: Musholic <musholic.tbg@gmail.com>

.github/workflows/test.yml

@@ -15,6 +15,7 @@ jobs:
       - name: Run tests
         run: busted --lua=luajit
       - name: Report coverage
+        continue-on-error: true # May fail on server errors (of coveralls.io)
         run: cd src; luacov-coveralls --repo-token=${{ secrets.github_token }} -e TestData -e Data -e runtime
   check_modcache:
     runs-on: ubuntu-latest