Delete TravisCI related content (#1427)

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Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

README.md

@@ -4,7 +4,6 @@
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/kanisterio/kanister)](https://goreportcard.com/report/github.com/kanisterio/kanister)
 [![GitHub Actions](https://github.com/kanisterio/kanister/actions/workflows/main.yaml/badge.svg)](https://github.com/kanisterio/kanister/actions)
-[![Build Status](https://travis-ci.com/kanisterio/kanister.svg?branch=master)](https://travis-ci.com/kanisterio/kanister)
 
 A framework for data management in Kubernetes.  It allows domain experts to
 define application-specific data management workflows through Kubernetes API

docs/index.rst

@@ -8,8 +8,8 @@ Kanister: Application-Specific Data Management
 
 .. image:: https://goreportcard.com/badge/github.com/kanisterio/kanister
    :target: https://goreportcard.com/report/github.com/kanisterio/kanister
-.. image:: https://travis-ci.org/kanisterio/kanister.svg?branch=master
-   :target: https://travis-ci.org/kanisterio/kanister
+.. image:: https://github.com/kanisterio/kanister/actions/workflows/main.yaml/badge.svg?branch=master
+   :target: https://github.com/kanisterio/kanister/actions
 
 Kanister allows domain experts to capture application-specific data management
 tasks in Blueprints which can be easily shared and extended. The framework takes