Update checkout action to v2

Author: bilal-alsharifi

.github/workflows/android.yml

@@ -8,7 +8,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Setup JDK
       uses: actions/setup-java@v1