LUCENE-9647 Add back github action for Ant (#2163)

.github/workflows/ant.yml

@@ -0,0 +1,32 @@
+name: Ant precommit
+
+on: 
+  pull_request:
+    branches:
+    - 'branch_8x'
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+
+    - name: Cache Ivy packages
+      uses: actions/cache@v2
+      with:
+        path: ~/.ivy2/cache/
+        key: ${{ runner.os }}-ant-precommit-${{ hashFiles('**/ivy-versions.properties') }}
+        restore-keys: |
+          ${{ runner.os }}-ant-precommit-
+          ${{ runner.os }}-ant-
+
+    - name: Ivy bootstrap
+      run: ant ivy-bootstrap
+
+    - name: Precommit
+      run: ant precommit