Add GitHub Actions workflow for Gradle build

Author: Technofied

.github/workflows/build.yml

@@ -0,0 +1,42 @@
+name: Build
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "21"
+          cache: gradle
+
+      - name: Make Gradle wrapper executable
+        run: chmod +x ./gradlew
+
+      - name: Build shadowJar
+        run: ./gradlew shadowJar
+
+      - name: Determine jar name
+        id: jar
+        shell: bash
+        run: |
+          JAR_PATH="$(ls -1 build/libs/*-all.jar | head -n 1)"
+          JAR_FILE="$(basename "$JAR_PATH")"
+          echo "path=$JAR_PATH" >> "$GITHUB_OUTPUT"
+          echo "name=$JAR_FILE" >> "$GITHUB_OUTPUT"
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ steps.jar.outputs.name }}
+          path: ${{ steps.jar.outputs.path }}
+          if-no-files-found: error