Clean up GH actions

.github/workflows/build.yaml

@@ -7,10 +7,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Set up JDK 11
+      - name: Set up JDK 16
         uses: actions/setup-java@v1
         with:
-          java-version: 11
+          java-version: 16
       - uses: actions/cache@v2
         with:
           path: |

.github/workflows/test.yaml

@@ -11,7 +11,5 @@ jobs:
         uses: actions/setup-java@v1
         with:
           java-version: 16
-      - name: Use gradle 7.0 pre 1 for Java 16 test
-        run: sed -i "s/6\.8/7.0-rc-1/" gradle/wrapper/gradle-wrapper.properties
       - name: Test on Java 16
         run: ./gradlew common:test --rerun-tasks