Delete old TravisCI workflow and references.

README.md

@@ -4,7 +4,6 @@
 [![Supported Python versions](https://img.shields.io/pypi/pyversions/ujson.svg?logo=python&logoColor=FFE873)](https://pypi.org/project/ujson)
 [![PyPI downloads](https://img.shields.io/pypi/dm/ujson.svg)](https://pypistats.org/packages/ujson)
 [![GitHub Actions status](https://github.com/ultrajson/ultrajson/workflows/Test/badge.svg)](https://github.com/ultrajson/ultrajson/actions)
-[![Travis CI status](https://travis-ci.com/ultrajson/ultrajson.svg?branch=main)](https://app.travis-ci.com/github/ultrajson/ultrajson)
 [![codecov](https://codecov.io/gh/ultrajson/ultrajson/branch/main/graph/badge.svg)](https://codecov.io/gh/ultrajson/ultrajson)
 [![DOI](https://zenodo.org/badge/1418941.svg)](https://zenodo.org/badge/latestdoi/1418941)
 [![Code style: Black](https://img.shields.io/badge/code%20style-Black-000000.svg)](https://github.com/psf/black)

RELEASING.md

@@ -1,11 +1,9 @@
 # Release Checklist
 
 - [ ] Get `main` to the appropriate code release state.
-      [GitHub Actions](https://github.com/ultrajson/ultrajson/actions) and
-      [Travis CI](https://app.travis-ci.com/github/ultrajson/ultrajson) should be running
+      [GitHub Actions](https://github.com/ultrajson/ultrajson/actions) should be running
       cleanly for all merges to `main`.
       [![GitHub Actions status](https://github.com/ultrajson/ultrajson/workflows/Test/badge.svg)](https://github.com/ultrajson/ultrajson/actions)
-      [![Build Status](https://app.travis-ci.com/ultrajson/ultrajson.svg?branch=main)](https://app.travis-ci.com/ultrajson/ultrajson)
 
 - [ ] Edit release draft, adjust text if needed: https://github.com/ultrajson/ultrajson/releases