github: add build workflow

.github/workflows/build.yaml

@@ -0,0 +1,20 @@
+name: Java CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: "17"
+          distribution: "temurin"
+      - name: Validate Gradle wrapper
+        uses: gradle/wrapper-validation-action@e6e38bacfdf1a337459f332974bb2327a31aaf4b
+      - name: Build with Gradle
+        uses: gradle/gradle-build-action@67421db6bd0bf253fb4bd25b31ebb98943c375e1
+        with:
+          arguments: build