ci: add release workflow

.github/workflows/release.yml

@@ -0,0 +1,64 @@
+name: GHCR Release CI
+
+on:
+  push:
+    tags:
+      - "[0-9]+.[0-9]+.[0-9]+"
+
+env:
+  HAS_SECRETS: ${{ secrets.HAS_SECRETS }}
+
+jobs:
+  tests:
+    name: Release new Docker Image in GHCR
+    strategy:
+      matrix:
+        python-version: [3.12]
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 60
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Initialise gopass
+        uses: camptocamp/initialise-gopass-summon-action@v2
+        with:
+          ci-gpg-private-key: ${{secrets.CI_GPG_PRIVATE_KEY}}
+          github-gopass-ci-token: ${{secrets.GOPASS_CI_GITHUB_TOKEN}}
+        if: env.HAS_SECRETS == 'HAS_SECRETS'
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Upgrade pip version
+        run: |
+          python -m pip install -U pip
+
+      - run: echo "${HOME}/.local/bin" >> ${GITHUB_PATH}
+
+      - name: Install CI dependencies
+        run: python3 -m pip install --user --requirement=ci/requirements.txt
+
+      - name: Environment information
+        run: c2cciutils-env
+        env:
+          GITHUB_EVENT: ${{ toJson(github) }}
+
+      - name: Login to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{github.repository_owner}}
+          password: ${{secrets.GITHUB_TOKEN}}
+
+      - name: Build Docker images for GHCR
+        run: make build_ghcr
+
+      - name: Push Docker images to GHCR
+        run: make push_ghcr