Add `workflow_dispatch` trigger for Docker builds

.github/workflows/build-and-push-docker-image.yml

@@ -6,7 +6,12 @@ on:   # yamllint disable-line rule:truthy
   pull_request:
   push:
     branches: ["release/*", "unstable/*"]
-    tags: ["*"]
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: Docker image tag
+        required: true
+        type: string
 
 jobs:
   build-and-push:
@@ -16,12 +21,14 @@ jobs:
     - uses: actions/checkout@v4
     - name: Build Docker image
       run: |
-        IMAGE="ghcr.io/$GITHUB_REPOSITORY:${GITHUB_REF_NAME/'/'/'-'}"
+        IMAGE="ghcr.io/$GITHUB_REPOSITORY:${DOCKER_TAG/'/'/'-'}"
         echo "IMAGE=$IMAGE" >>"$GITHUB_ENV"
         docker build . \
           --build-arg BUILDKIT_INLINE_CACHE=1 \
           --cache-from $IMAGE \
           --tag $IMAGE
+      env:
+        DOCKER_TAG: ${{ inputs.tag || github.ref_name }}
     - name: Log in to GHCR
       if: github.event_name != 'pull_request'
       run: >-