.github: add workflow to build beta images

.github/workflows/build-images-beta.yaml

@@ -0,0 +1,129 @@
+name: Beta Image Release Build
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Docker Image Tag'
+        required: true
+
+permissions: read-all
+
+jobs:
+  build-and-push:
+    if: ${{ github.repository == 'cilium/cilium' }}
+    environment: release-beta-images
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        include:
+          - name: cilium
+            dockerfile: ./images/cilium/Dockerfile
+
+          - name: operator
+            dockerfile: ./images/operator/Dockerfile
+
+          - name: operator-aws
+            dockerfile: ./images/operator/Dockerfile
+
+          - name: operator-azure
+            dockerfile: ./images/operator/Dockerfile
+
+          - name: operator-alibabacloud
+            dockerfile: ./images/operator/Dockerfile
+
+          - name: operator-generic
+            dockerfile: ./images/operator/Dockerfile
+
+          - name: hubble-relay
+            dockerfile: ./images/hubble-relay/Dockerfile
+
+          - name: clustermesh-apiserver
+            dockerfile: ./images/clustermesh-apiserver/Dockerfile
+
+          - name: docker-plugin
+            dockerfile: ./images/cilium-docker-plugin/Dockerfile
+
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@94ab11c41e45d028884a99163086648e898eed25
+
+      - name: Login to quay.io
+        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
+        with:
+          registry: quay.io
+          username: ${{ secrets.QUAY_BETA_USERNAME }}
+          password: ${{ secrets.QUAY_BETA_PASSWORD }}
+
+      - name: Getting image tag
+        id: tag
+        run: |
+          echo ::set-output name=tag::${GITHUB_REF##*/}
+
+      - name: Checking if tag already exists
+        id: tag-in-repositories
+        shell: bash
+        run: |
+          if docker buildx imagetools inspect quay.io/${{ github.repository_owner }}/${{ matrix.name }}-beta:${{ github.event.inputs.tag }} &>/dev/null; then
+            echo "Tag already exists!"
+            exit 1
+          fi
+
+      - name: Checkout Source Code
+        uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
+        with:
+          persist-credentials: false
+
+      - name: Release Build ${{ matrix.name }}
+        uses: docker/build-push-action@a66e35b9cbcf4ad0ea91ffcaf7bbad63ad9e0229
+        id: docker_build_release
+        with:
+          context: .
+          file: ${{ matrix.dockerfile }}
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: |
+            quay.io/${{ github.repository_owner }}/${{ matrix.name }}-beta:${{ github.event.inputs.tag }}
+            quay.io/${{ github.repository_owner }}/${{ matrix.name }}-ci:${{ github.sha }}
+          build-args: |
+            OPERATOR_VARIANT=${{ matrix.name }}
+
+      - name: Image Release Digest
+        shell: bash
+        run: |
+          mkdir -p image-digest/
+          echo "## ${{ matrix.name }}" > image-digest/${{ matrix.name }}.txt
+          echo "" >> image-digest/${{ matrix.name }}.txt
+          echo "\`quay.io/${{ github.repository_owner }}/${{ matrix.name }}-beta:${{ github.event.inputs.tag }}@${{ steps.docker_build_release.outputs.digest }}\`" >> image-digest/${{ matrix.name }}.txt
+          echo "\`quay.io/${{ github.repository_owner }}/${{ matrix.name }}-ci:${{ github.sha }}@${{ steps.docker_build_release.outputs.digest }}\`" >> image-digest/${{ matrix.name }}.txt
+          echo "" >> image-digest/${{ matrix.name }}.txt
+
+      # Upload artifact digests
+      - name: Upload artifact digests
+        uses: actions/upload-artifact@27121b0bdffd731efa15d66772be8dc71245d074
+        with:
+          name: image-digest ${{ matrix.name }}
+          path: image-digest
+          retention-days: 1
+
+  image-digests:
+    if: ${{ github.repository == 'cilium/cilium' }}
+    name: Display Digests
+    runs-on: ubuntu-20.04
+    needs: build-and-push
+    steps:
+      - name: Downloading Image Digests
+        shell: bash
+        run: |
+          mkdir -p image-digest/
+
+      - name: Download digests of all images built
+        uses: actions/download-artifact@3be87be14a055c47b01d3bd88f8fe02320a9bb60
+        with:
+          path: image-digest/
+
+      - name: Image Digests Output
+        shell: bash
+        run: |
+          cd image-digest/
+          find -type f | sort | xargs -d '\n' cat