Replace AppVeyor by GitHub actions

Build on JDK 11 and JDK 17 and upload the build artifacts

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+---
+name: Gradle
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        java: [11, 17, 21]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK ${{ matrix.java }}
+        uses: actions/setup-java@v4
+        with:
+          java-version: ${{ matrix.java }}
+          distribution: 'zulu'
+      - name: Run commands
+        run: |
+          ./gradlew build
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: omero-ms-image-region ${{ matrix.java }}
+          path: build/distributions/*