CI: build the Lyrica image only when ./lyrica changes (its own workflow), so a Docker Hub timeout cannot fail the main build

.gitea/workflows/build-lyrica.yml

@@ -0,0 +1,37 @@
+name: build-lyrics-container
+
+# The lyrics container (Lyrica, pinned to one commit) only changes when ./lyrica does, so it is built only then (or by hand with "Run workflow").
+# Building it on every push meant a needless restart of the lyrics service each time, and a failed pull of its Python base image failed the whole run.
+on:
+  push:
+    branches: [main]
+    paths: ['lyrica/**', '.gitea/workflows/build-lyrica.yml']
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          registry: git.necloud.us
+          username: ${{ secrets.REGISTRY_USER || gitea.actor }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+      - id: meta_ly
+        uses: docker/metadata-action@v5
+        with:
+          images: git.necloud.us/nate/hub-lyrica
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=sha,format=short
+      - uses: docker/build-push-action@v6
+        with:
+          context: ./lyrica
+          platforms: linux/amd64
+          push: true
+          tags: ${{ steps.meta_ly.outputs.tags }}
+          labels: ${{ steps.meta_ly.outputs.labels }}
+          cache-from: type=registry,ref=git.necloud.us/nate/hub-lyrica:buildcache
+          cache-to: type=registry,ref=git.necloud.us/nate/hub-lyrica:buildcache,mode=max