Remove unused maven plugin (fix build error on react-native 0.67)

[hoangvvo]

On react-native@0.67, gradle is updated to v7 (https://react-native-community.github.io/upgrade-helper/?from=0.66.4&to=0.67.1). This version deprecate the plugin maven in favor of maven-publish (this used to give a deprecation message on v6). Therefore, when using the library with react-native v0.67, it will not work:

* Where:
Build file '/node_modules/react-native-spotify-remote/android/build.gradle' line: 10

* What went wrong:
A problem occurred evaluating project ':react-native-spotify-remote'.
> Plugin with id 'maven' not found.

However, this library does not really use maven-publish at all (maven-publish publishes build artifact to Apache Maven). So this PR fixes this issue by removing the plugin completely.

I have tested this to be working in my own project.

[cjam]

Thanks for the contribution!

[cjam]

Sorry for the delay on this, I've released it under 0.3.11-5