Fix dev builds from specific branch

Author: butschster

.github/workflows/docker-dev-image.yml

@@ -40,5 +40,6 @@ jobs:
           push: true
           build-args:
             APP_VERSION=${{ steps.previoustag.outputs.tag }}
+            BRANCH=${{ steps.previoustag.outputs.tag }}
           tags:
             ghcr.io/${{ github.repository }}:dev, ghcr.io/${{ github.repository }}:${{ steps.previoustag.outputs.tag }}