Merge pull request 'ci: filter main builds to code changes and cancel superseded runs' (#18) from ci/optimise-main-builds into main

Reviewed-on: #18

.gitea/workflows/build-and-publish.yml

@@ -1,10 +1,30 @@
 name: Build and publish container
 
 on:
+  # On merge to main, only build/release when image-affecting files change;
+  # CI-config, Renovate-config and docs changes do not produce a new image.
   push:
     branches: [main]
+    paths:
+      - 'Dockerfile'
+      - 'default.conf'
+      - 'index.html'
+      - 'styles.css'
+      - 'script.js'
+      - 'messages.js'
+      - '.dockerignore'
+  # Pull requests always run (the build is a required check); no path filter.
   pull_request:
     branches: [main]
+  workflow_dispatch:
+
+# A newer run cancels an older in-flight run in the same group (keyed by ref),
+# so a fresh merge to main supersedes the previous build and only the latest
+# release is produced, avoiding tags that would be immediately replaced. Each
+# pull request likewise supersedes only its own earlier runs.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 defaults:
   run:
@@ -94,21 +114,21 @@ jobs:
           echo "Computed bump=${bump}, release=${release}, base=${base}"
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3
+        uses: docker/setup-qemu-action@06116385d9baf250c9f4dcb4858b16962ea869c3 # v4
 
       - name: Set up Buildx
-        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
+        uses: docker/setup-buildx-action@d7f5e7f509e45cec5c76c4d5afdd7de93d0b3df5 # v4
 
       - name: Log in to the Gitea container registry
         if: github.event_name != 'pull_request'
-        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
+        uses: docker/login-action@650006c6eb7dba73a995cc03b0b2d7f5ca915bee # v4
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.repository_owner }}
           password: ${{ secrets.PACKAGES_TOKEN }}
 
       - name: Build and push
-        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
+        uses: docker/build-push-action@f9f3042f7e2789586610d6e8b85c8f03e5195baf # v7
         with:
           context: .
           platforms: linux/amd64,linux/arm64