v0.2.0 Initial GKE Support

Changelog

80f0187 Merge pull request #4 from reactiveops/rs/gke-integration
edee377 Merge pull request #5 from reactiveops/rs/fix-circle-release-config
ba8db1f adding --gke flag, some related cleanup and restructuring
7589a89 adding GKE specific tests, updating GKE role mapping
cc2171d adding link to lookup/gke_roles.go in readme
57b01d2 bumping version to 0.2.0
067dc84 fixing CircleCI release config
0ff63d4 fixing typo in readme
c4bdc2b initial very rough gke support + moving to dep and go 1.11
e243c15 updating readme to include GKE integration