ci: deprecate Travis CI

.travis.yml

@@ -1,28 +0,0 @@
-language: go
-
-stages:
-  - test
-  - build
-
-go:
-  - 1.14.x
-  - 1.15.x
-  - tip
-
-env: GO111MODULE=on
-
-before_install:
-  - go get -u github.com/kyoh86/richgo
-  - go get -u github.com/mitchellh/gox
-  - curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin latest
-
-matrix:
-  allow_failures:
-    - go: tip
-  include:
-    - stage: build
-      go: 1.14.x
-      script: make cobra_generator
-
-script:
- - make test

README.md

@@ -7,7 +7,6 @@ Cobra is used in many Go projects such as [Kubernetes](http://kubernetes.io/),
 name a few. [This list](./projects_using_cobra.md) contains a more extensive list of projects using Cobra.
 
 [![](https://img.shields.io/github/workflow/status/spf13/cobra/Test?longCache=tru&label=Test&logo=github%20actions&logoColor=fff)](https://github.com/spf13/cobra/actions?query=workflow%3ATest)
-[![Build Status](https://travis-ci.org/spf13/cobra.svg "Travis CI status")](https://travis-ci.org/spf13/cobra)
 [![GoDoc](https://godoc.org/github.com/spf13/cobra?status.svg)](https://godoc.org/github.com/spf13/cobra)
 [![Go Report Card](https://goreportcard.com/badge/github.com/spf13/cobra)](https://goreportcard.com/report/github.com/spf13/cobra)
 [![Slack](https://img.shields.io/badge/Slack-cobra-brightgreen)](https://gophers.slack.com/archives/CD3LP1199)