Update grandle plugin to 3.0.1

[nikitin-da]

Closes #851

Changelogs:
Gradle plugin: https://developer.android.com/studio/releases/gradle-plugin.html

We have to update these dependencies too:
Support libs: https://developer.android.com/topic/libraries/support-library/revisions.html
Robolectric: https://github.com/robolectric/robolectric/releases
LeakCanary https://github.com/square/leakcanary/blob/master/CHANGELOG.md

[codecov-io]

Codecov Report

Merging #862 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #862   +/-   ##
=========================================
  Coverage     97.66%   97.66%           
  Complexity      829      829           
=========================================
  Files            98       98           
  Lines          2744     2744           
  Branches        302      302           
=========================================
  Hits           2680     2680           
  Misses           35       35           
  Partials         29       29

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