Update .gitignore

Author: doup

.gitignore

@@ -39,6 +39,10 @@ project.xcworkspace
 .settings
 local.properties
 android.iml
+android/gradlew
+android/gradlew.bat
+android/gradle/wrapper/gradle-wrapper.jar
+android/gradle/wrapper/gradle-wrapper.properties
 
 # Cocoapods
 #
@@ -47,6 +51,7 @@ example/ios/Pods
 # node.js
 #
 node_modules/
+package-lock.json
 npm-debug.log
 yarn-debug.log
 yarn-error.log