remove gradle files from git cache

Merge pull request #1050 from OneSignal/release_5.3.4

Release 5.3.4

Merge pull request #1041 from OneSignal/rel/5.3.3

Release 5.3.3

Merge pull request #1029 from OneSignal/rel/5.3.2

Release 5.3.2

Merge pull request #1027 from OneSignal/rel/5.3.1

Release 5.3.1

Merge pull request #1012 from OneSignal/rel/5.3.0

Release 5.3.0

Merge pull request #982 from OneSignal/rel/5.2.9

Release 5.2.9

Merge pull request #976 from OneSignal/rel/5.2.8

Release 5.2.8

Merge pull request #969 from OneSignal/rel/5.2.7

Release 5.2.7

Merge pull request #962 from OneSignal/rel/3.5.4

Release 3.5.4