ci: add tag-driven release workflow

Author: jamjet3

.github/workflows/release.yml

@@ -3,45 +3,66 @@ name: Release
 on:
   push:
     tags:
-      - 'v*.*.*'
-  workflow_dispatch:
-
-permissions:
-  contents: write
+      - 'v*'          # e.g. v1.2.0 or v1.3.0-rc.1
 
 jobs:
   build-and-release:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write   # needed to create a Release & upload assets
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Validate Gradle Wrapper
-        uses: gradle/wrapper-validation-action@v2
+      - name: Validate Gradle wrapper
+        uses: gradle/actions/wrapper-validation@v4
 
-      - name: Set up Java 21
+      - name: Set up Temurin JDK 21
         uses: actions/setup-java@v4
         with:
-          distribution: temurin
+          distribution: 'temurin'
           java-version: '21'
-          cache: gradle
 
-      - name: Grant execute permission for gradlew
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Make gradlew executable
         run: chmod +x gradlew
 
-      - name: Build (fat jar)
-        run: ./gradlew --no-daemon clean build
+      # Build the fat JAR (we replaced Shadow with the 'uberJar' task)
+      - name: Build
+        run: ./gradlew --no-daemon clean uberJar
 
-      - name: Archive jars
-        uses: actions/upload-artifact@v4
-        with:
-          name: modnvote-jars
-          path: build/libs/*.jar
+      # Work out version & jar path
+      - name: Compute version and artifact path
+        id: vars
+        shell: bash
+        run: |
+          VERSION="$(grep -oP 'version\\s*=\\s*\"\\K[^\"]+' build.gradle.kts)"
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          JAR_PATH="$(ls build/libs/*.jar | head -n1)"
+          echo "jar=$JAR_PATH" >> "$GITHUB_OUTPUT"
+
+      - name: Generate checksums
+        run: |
+          sha256sum "${{ steps.vars.outputs.jar }}" > checksums.txt
 
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v2
         with:
-          files: build/libs/*.jar
-          generate_release_notes: true
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          tag_name: ${{ github.ref_name }}              # the pushed tag (e.g. v1.2.0)
+          name: ModNVote ${{ steps.vars.outputs.version }}
+          body: |
+            Automated release for ModNVote ${{ steps.vars.outputs.version }}.
+
+            **Changes**
+            - See commit history for this tag.
+
+            **Checksums**
+            - Provided in `checksums.txt`.
+          files: |
+            ${{ steps.vars.outputs.jar }}
+            checksums.txt
+          draft: false
+          prerelease: ${{ contains(github.ref_name, '-rc') || contains(github.ref_name, '-beta') }}