fixes push only on merge or tag

Author: domonik

.github/workflows/build_docker.yml

@@ -33,7 +33,7 @@ jobs:
         with:
           context: .
           file: ./Dockerfile
-          push: true
+          push: ${{ github.event_name == 'push' }}
           tags: |
             ${{ secrets.DOCKERHUB_USERNAME }}/rnadist:${{ startsWith(github.ref, 'refs/tags/') && 'latest' || 'nightly' }}
             ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || format('{0}/rnadist:nightly-{1}', secrets.DOCKERHUB_USERNAME, github.sha) }}