Add pipeline to publish ghcr multi-arch image (#2268)

Refactor operator image build process
Add a pipeline to build and publish arm64/amd64 image in ghcr on every
pushed tag

.github/workflows/publish_ghcr_image.yaml

@@ -0,0 +1,56 @@
+name: Publish multiarch postgres-operator image on ghcr.io
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+on:
+  push:
+    tags:
+      - '*'
+jobs:
+  publish:
+    name: Build, test and push image
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: "^1.18.9"
+
+      - name: Run unit tests
+        run: make deps mocks test
+
+      - name: Define image name
+        id: image
+        run: |
+            IMAGE="${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${GITHUB_REF/refs\/tags\//}"
+            echo "NAME=$IMAGE" >> $GITHUB_OUTPUT
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to GHCR
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push multiarch image to ghcr
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          file: docker/Dockerfile
+          push: true
+          build-args: BASE_IMAGE=alpine:3.15
+          tags: "${{ steps.image.outputs.NAME }}"
+          platforms: linux/amd64,linux/arm64

.github/workflows/run_e2e.yaml

@@ -19,8 +19,6 @@ jobs:
       run: make deps mocks
     - name: Code generation
       run: make codegen
-    - name: Compile
-      run: make linux
     - name: Run unit tests
       run: make test
     - name: Run end-2-end tests