Add mavenCentral() as repository

[RTK]

Right now the compilation with the plugin under Android won't work since it is missing the mavenCentral() repository:

RIght now:

buildscript {
    repositories {
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.2.1'
    }
}

Should be:

buildscript {
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.2.1'
    }
}

Otherwise it won't be able to resolve dependencies in the compilation phase.