Update dependency com.android.tools.build:gradle to v3.6.4

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
com.android.tools.build:gradle (source)	3.0.1 -> 3.6.4
com.android.tools.build:gradle (source)	3.2.1 -> 3.6.4

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