Fix GitHub workflow

Author: zsmb13

.github/workflows/pull-request.yml

@@ -9,9 +9,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: set up JDK 1.8
-      uses: actions/setup-java@v1
+    - name: Set up JDK 11
+      uses: actions/setup-java@v2
       with:
-        java-version: 1.8
+        distribution: adopt
+        java-version: 11
     - name: Build app
       run: ./gradlew assembleDebug