Add docker build and push workflow

.github/workflows/publish-docker.yml

@@ -0,0 +1,84 @@
+name: Build and Publish Docker Image
+
+on:
+  release:
+    types:
+    - published
+  push:
+    branches:
+    - gep/inplace-node-update
+    tags:
+    - v*
+    paths-ignore:
+    - 'docs/**'
+    - '**/*.md'
+  pull_request:
+    types:
+    - labeled
+    paths-ignore:
+    - 'docs/**'
+    - '**/*.md'
+
+jobs:
+  buildAndPush:
+    strategy:
+      matrix:
+        image:
+        - name: gardener-apiserver
+          target: apiserver
+        - name: gardener-node-agent
+          target: node-agent
+    permissions:
+      contents: read
+      packages: write
+    if: ${{ github.event.label.name == 'ok-to-image' }} || ${{ github.event.label.name == 'ok-to-🐳' }} || ${{ github.ref == 'refs/heads/main' }}
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: docker/metadata-action@v5
+      id: meta
+      with:
+        images: |
+          ghcr.io/${{ github.repository_owner }}/${{ matrix.image.name }}
+        tags: |
+          type=semver,pattern={{version}}
+          type=schedule
+          type=ref,event=branch
+          type=ref,event=tag
+          type=ref,event=pr
+          type=sha
+        flavor: |
+          latest=${{ github.ref == 'refs/heads/gep/inplace-node-update' }}
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v3
+      with:
+        platforms: all
+    # workaround for self-hosted runner
+    # https://github.com/mumoshu/actions-runner-controller-ci/commit/e91c8c0f6ca82aa7618010c6d2f417aa46c4a4bf
+    - name: Set up Docker Context for Buildx
+      id: buildx-context
+      run: |
+        docker context create builders
+    - name: Set up Docker Buildx
+      timeout-minutes: 5
+      uses: docker/setup-buildx-action@v3
+      with:
+        version: latest
+        endpoint: builders # self-hosted
+    - name: Login to GHCR
+      if: github.event_name != 'pull_request'
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+    - name: Build and push
+      timeout-minutes: 40
+      uses: docker/build-push-action@v6
+      with:
+        context: .
+        platforms: linux/amd64
+        push: ${{ github.event_name != 'pull_request' }}
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}
+        target: ${{ matrix.image.target }}