fix: Use github ref name

Signed-off-by: Julius Härtl <[email protected]>

Author: juliusknorr

.github/workflows/docker.yml

@@ -91,7 +91,7 @@ jobs:
           file: ${{ steps.dockerfile.outputs.DOCKERFILE }}
           tags: |
             ghcr.io/juliushaertl/nextcloud-dev-${{ matrix.container }}:${{ github.event_name == 'release' && 'latest' || 'nightly' }}
-            ghcr.io/juliushaertl/nextcloud-dev-${{ matrix.container }}:${{ github.event_name == 'release' && github.ref || github.sha }}
+            ghcr.io/juliushaertl/nextcloud-dev-${{ matrix.container }}:${{ github.ref_name }}
           cache-from: type=local,src=/tmp/.buildx-cache
           cache-to: type=local,dest=/tmp/.buildx-cache-new
       - name: Move cache