Both the plugin SDK and Terraform itself are using Go 1.12.9. This updates use to that version as well as updating Travis to test on 1.12.x and 1.13.x https://github.com/hashicorp/terraform/blob/master/.go-version https://github.com/hashicorp/terraform-plugin-sdk/blob/master/.go-version
provider: Run go fix provider: Run go fmt provider: Encode go version 1.11.5 to .go-version file