Update test-and-build-workflow.yml (opendistro-for-elasticsearch#185)

* Update test-and-build-workflow.yml

* Update test-and-build-workflow.yml

.github/workflows/test-and-build-workflow.yml

@@ -8,22 +8,19 @@ on:
 
 jobs:
   build:
-    strategy:
-      matrix:
-        java: [12]
     # Job name
-    name: Build Index Management with JDK ${{ matrix.java }}
+    name: Build Index Management
     # This job runs on Linux
     runs-on: ubuntu-latest
     steps:
       # This step uses the checkout Github action: https://github.com/actions/checkout
       - name: Checkout Branch
         uses: actions/checkout@v1
       # This step uses the setup-java Github action: https://github.com/actions/setup-java
-      - name: Set Up JDK ${{ matrix.java }}
+      - name: Set Up JDK 12
         uses: actions/setup-java@v1
         with:
-          java-version: ${{ matrix.java }}
+          java-version: 12
       - name: Build with Gradle
         run: ./gradlew build
       - name: Create Artifact Path