Add tests workflow.

Author: mzitnik

.github/workflows/tests.yaml

@@ -0,0 +1,20 @@
+name: Apache Flink ClickHouse Connector Tests CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Apache Flink ClickHouse Connector tests
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: '21'
+          distribution: 'adopt'
+          architecture: x64
+      - name: Setup and execute Gradle 'test' task
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: test