Attempt to fix build

Signed-off-by: Mario Danic <mario@lovelyhq.com>

build.gradle

@@ -167,6 +167,10 @@ android {
     }
     check.dependsOn 'checkstyle', 'findbugs', 'pmd', 'lint'
 
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 }
 
 dependencies {