feat(ci): add docker ci on github

Author: janezicmatej

.github/workflows/build-docker.yml

@@ -0,0 +1,61 @@
+name: container-images
+
+on:
+  push:
+    branches: [ "main" ]
+    tags: [ "v*" ]
+
+jobs:
+  build-container-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - uses: docker/setup-qemu-action@v3
+    - uses: docker/setup-buildx-action@v3
+
+    - name: Set ALL_TAGS
+      env:
+        REPOSITORY: '${{ github.repository }}'
+      run: |
+        # tag main if main branch
+        if [[ "${{ github.ref_name }}" == "main" ]]; then
+          image_tags=("main")
+        # tag with tag name if tag
+        elif [[ "${{ github.ref }}" == refs/tags/v* ]]; then
+          image_tags=("${{ github.ref_name }}")
+          # tag with latest if tag is a new major, minor or patch version
+          if [[ "${{ github.ref_name}}" =~ ^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$ ]]; then
+            image_tags+=("latest")
+          fi
+        fi
+
+        lc_repo=${REPOSITORY,,}
+
+        image_paths=()
+        for tag in ${image_tags[@]}; do
+          image_paths+=("ghcr.io/$lc_repo:$tag")
+        done
+
+        # join with ',' and then skip first character
+        ALL_TAGS=$(printf ',%s' "${image_paths[@]}")
+        echo "ALL_TAGS=${ALL_TAGS:1}" >>$GITHUB_ENV
+
+    - name: Login to ghcr.io
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build and push default image
+      uses: docker/build-push-action@v5
+      with:
+        context: . # Because GH actions are for kids and put protection on everything; https://stackoverflow.com/a/71159809/11276254
+        platforms: linux/amd64,linux/arm64
+        push: true
+        tags: ${{ env.ALL_TAGS }}