Remove cirrus CI (OpenAI acquired it)

Author: SamuelMarks

.cirrus.yml

@@ -2,8 +2,6 @@ c89stringutils
 ==============
 [![License](https://img.shields.io/badge/license-Apache--2.0%20OR%20MIT-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![CI for Linux, Windows, macOS](https://github.com/offscale/c89stringutils/actions/workflows/ci.yml/badge.svg)](https://github.com/offscale/c89stringutils/actions/workflows/ci.yml)
-[![CI for FreeBSD](https://api.cirrus-ci.com/github/offscale/c89stringutils.svg)](https://cirrus-ci.com/github/offscale/c89stringutils)
-![coverage](reports/test_coverage.svg)
 [![C89](https://img.shields.io/badge/C-89-blue)](https://en.wikipedia.org/wiki/C89_(C_version))
 
 C89 is missing some nice things. As is MSVC.