ci: build RPC image automagically

.github/workflows/build-rpc-images.yml

@@ -0,0 +1,42 @@
+name: build-docker-rpc-images
+
+on:
+  pull_request_target:
+  push:
+    branches:
+      - main
+
+jobs:
+  deployment:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ secrets.DOCKERHUB_USERNAME }}/${{ secrets.DOCKERHUB_RPC_REPO }}
+          tags: |
+            type=ref,event=tag
+            type=ref,event=pr
+            type=raw,value=latest,enable=${{ github.ref == 'refs/heads/main' }}
+          labels: |
+            maintainer=bitcoindevproject
+            org.opencontainers.image.title=warnet-rpc
+            org.opencontainers.image.description=Warnet RPC server
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          file: src/templates/rpc/Dockerfile_rpc
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=registry,ref=${{ secrets.DOCKERHUB_USERNAME }}/${{ secrets.DOCKERHUB_RPC_REPO }}:latest
+          cache-to: type=inline