Update readme.md with RN >= 0.65.0 fixes

[RobertoNegro]

Resolves #72

In React Native 0.65.0 they removed jcenter() from the repositories in the android/build.gradle (proof: https://react-native-community.github.io/upgrade-helper/?from=0.64.2&to=0.65.0).

They removed it because jcenter is no more active, but it's reachable as a read-only repository (proof: https://developer.android.com/studio/build/jcenter-migration) so you can add it back if you need it, like in this case since com.google.vr is deprecated and ufficially it won't be uploaded to other active repositories.

[cristianoccazinsp]

I wonder if it would be possible to include the android aar files in the source so we don't need this dependency.