Fix release workflow syntax (missing with)

Refs #286

Author: joschi

.github/workflows/release.yml

@@ -48,7 +48,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2.4.0
-        ref: ${{ github.event.inputs.releaseVersion }}
+        with:
+          ref: ${{ github.event.inputs.releaseVersion }}
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
       - name: Login to DockerHub