ci: upgrade GitHub Actions and add latest-<short-sha> image tag

.github/workflows/build.yml

@@ -12,26 +12,36 @@ jobs:
     steps:
       -
         name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
+      -
+        name: Short SHA
+        id: vars
+        run: echo "short_sha=${GITHUB_SHA:0:7}" >> $GITHUB_OUTPUT
       -
         name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
+        uses: docker/setup-qemu-action@v3
       -
         name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v1
+        uses: docker/setup-buildx-action@v3
       -
         name: Login to DockerHub
-        uses: docker/login-action@v1
+        uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       -
         name: Build and push
-        uses: docker/build-push-action@v2
+        id: docker_build
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true
-          tags: steemit/hivemind:latest
+          tags: |
+            steemit/hivemind:latest
+            steemit/hivemind:latest-${{ steps.vars.outputs.short_sha }}
       -
-        name: Image digest
-        run: echo ${{ steps.docker_build.outputs.digest }}
+        name: Pushed tags
+        run: |
+          echo "Pushed image tags:"
+          echo "  - steemit/hivemind:latest"
+          echo "  - steemit/hivemind:latest-${{ steps.vars.outputs.short_sha }}"

.github/workflows/pr-build.yml

@@ -0,0 +1,32 @@
+name: pr-docker-build
+
+on:
+  pull_request:
+    branches:
+      - 'master'
+
+jobs:
+  docker-build:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v4
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      -
+        name: Build (no push)
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: false
+          tags: hivemind:pr-check
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+      -
+        name: Build succeeded
+        run: echo "Docker image built successfully. No push to Docker Hub."