#412: Add worflow to release metal automatically but with manual trig…

…ger.

This workflow may only be triggered manually. The values of all the
secret variables are already included within GitHub. Only the license
year replacement and version within README is not implemented yet.

.github/workflows/release.yml

@@ -0,0 +1,87 @@
+# General workflow to build Metal
+
+name: Metal build
+
+on:
+  workflow_dispatch:
+    inputs:
+      doRelease:
+        description: 'Do release'
+        required: false
+        type: boolean
+      javaVersion:
+        description: 'Java version'
+        required: true
+        default: '11'
+        type: choice
+        options:
+          - '11'
+          - '17'
+      javaDistribution:
+        description: 'Java distribution'
+        required: true
+        default: 'corretto'
+        type: choice
+        options:
+          - 'corretto'
+          - 'temurin'
+
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    if: github.ref_name == 'main' && ${{ inputs.doRelease }}
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set up Cache
+        uses: actions/cache@v3
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: |
+            ${{ runner.os }}-maven-
+
+      - name: Set up JDK
+        uses: actions/setup-java@v3
+        with:
+          java-version: ${{ inputs.javaVersion }}
+          distribution: ${{ inputs.javaDistribution }}
+
+        # See more details about setting secret keys https://gist.github.com/sualeh/ae78dc16123899d7942bc38baba5203c
+      - name: Install gpg secret key
+        id: install-secret-key
+        run: |
+          # Install gpg secret key
+          cat <(echo -e "${{ secrets.OSSRH_GPG_SECRET_KEY }}") | gpg --batch --import
+          # Verify gpg secret key
+          gpg --list-secret-keys --keyid-format LONG
+
+      - name: Update License headers
+        run: |
+          mavenVersion=$( mvn help:evaluate -Dexpression=project.version -q -DforceStdout); 
+          version=${mavenVersion%%-SNAPSHOT};
+          echo Update headers here.
+          echo Update README here.
+
+      - name: Release prepare
+        run: mvn -B release:prepare release:clean
+
+      - name: Checkout to latest tag
+        run: git checkout $(git describe --tags --abbrev=0)
+
+      - name: Publish to Maven Central Repository
+        env:
+          MAVEN_USERNAME: ${{ secrets.OSSRH_USERNAME }}
+          MAVEN_PASSWORD: ${{ secrets.OSSRH_TOKEN }}
+        run: |
+          mvn \
+            --no-transfer-progress \
+            --batch-mode \
+            -Dgpg.passphrase=${{ secrets.OSSRH_GPG_SECRET_KEY_PASSWORD }} \
+            deploy -Prelease
+