Implement GHA PR checks

.github/workflows/build-prs.yml

@@ -0,0 +1,51 @@
+name: Build and test PRs
+
+on:
+  pull_request:
+    types:
+      - synchronize
+      - opened
+      - ready_for_review
+      - reopened
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1000
+          fetch-tags: true
+
+      # GradleUtils will append the branch name to the version,
+      # but for that we need a properly checked out branch
+      - name: Create branch for commit
+        run:
+          git switch -C pr-${{ github.event.pull_request.number }}-${{ github.event.pull_request.head.ref }}
+
+      - name: Setup JDK 17
+        uses: actions/setup-java@v2
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Setup with Gradle
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: setup
+
+      - name: Build with Gradle
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: build
+
+      - name: Checks ATs, patches, etc...
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: checkAll
+
+      - name: Checks JAR compatibility
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: checkJarCompatibility