Support gradle 7

[aiden-petersen]

• Firstly I've refreshed the example app using react-native init....
• I've also made the example app reference the project files in the parent folder instead of pulling from the published one.
• Finally I've then updated the android build.gradle with a more modern implementation and removed code that was incompatible with gradle 7.

[aiden-petersen]

@HwangTaehyun I've updated the example app and removed the afterEvaluate code. I've tested this on both RN 0.69.0 and 0.66.0.

[HwangTaehyun]

Thanks @aiden-petersen!
I will check it!

[HwangTaehyun]

It works well! @aiden-petersen