Merge pull request joltup#212 from nnrohu/patch-1

Update build.gradle

Author: RonRadtke

android/build.gradle

@@ -59,6 +59,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+    compileOptions {
+       sourceCompatibility JavaVersion.VERSION_1_8
+       targetCompatibility JavaVersion.VERSION_1_8
+    }
     lintOptions {
         abortOnError false
     }
@@ -157,4 +161,4 @@ afterEvaluate { project ->
             }
         }
     }
-}
+}