bump gradle wrapper to 6.8.3

[dulmandakh]

Summary

This is preparation for Gradle 7.0 version, which supports Apple Silicon natively.

Changelog

[Android] [Changed] - Bump gradle wrapper to 6.8.3

Test Plan

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 2052bb6

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,853,485	+0
android	hermes	armeabi-v7a	8,374,856	+0
android	hermes	x86	9,310,441	+0
android	hermes	x86_64	9,253,440	+0
android	jsc	arm64-v8a	10,584,490	+0
android	jsc	armeabi-v7a	10,088,955	+0
android	jsc	x86	10,602,933	+0
android	jsc	x86_64	11,186,199	+0

Base commit: 2052bb6

[dulmandakh]

@fkgozali @mdvacca please review and merge

[facebook-github-bot]

@yungsters has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@yungsters merged this pull request in 7258afe.