Inconsistent tags for Android in project.xml (low priority)

[pfoof]

This is a minor issue but is worth noting:

• <android gradle-version="6.7.1" /> - changes gradle version in build.gradle
• <config:android gradle-plugin="4.2.0" /> - changes gradle plugin version
• <android gradle-plugin="4.2.0" /> - does not change gradle plugin version

Another worth noting thing is that config: should have a separate namespace with its own xsd file.

[player-03]

The <android /> tag is deprecated, though the only note of this is in a comment. Perhaps the solution is to start showing deprecation warnings.

I've seen warnings about the missing schema too, and it'd be nice to fix it, but I have other priorities.