Add build to coverage step.

Signed-off-by: Max Lambrecht <maxlambrecht@gmail.com>

.github/workflows/gradle.yml

@@ -32,7 +32,7 @@ jobs:
       - name: Generate and upload coverage report
         env:
           COVERALLS_REPO_TOKEN: ${{ secrets.CoverallsRepoToken }}
-        run: ./gradlew jacocoTestReport coveralls
+        run: ./gradlew build jacocoTestReport coveralls
       - uses: actions/upload-artifact@v2
         with:
           name: Package