Add cmake-cosmo status badge to README.md

Issue #666 (bdwgc).

README.md

@@ -3,6 +3,7 @@
 [![Travis-CI build status](https://app.travis-ci.com/ivmai/bdwgc.svg?branch=master)](https://app.travis-ci.com/github/ivmai/bdwgc)
 [![AppVeyor CI build status](https://ci.appveyor.com/api/projects/status/github/ivmai/bdwgc?branch=master&svg=true)](https://ci.appveyor.com/project/ivmai/bdwgc)
 [![GitHub Actions build status (cmake)](https://github.com/ivmai/bdwgc/actions/workflows/cmake-build.yml/badge.svg?event=push)](https://github.com/ivmai/bdwgc/actions/workflows/cmake-build.yml?query=branch%3Amaster)
+[![GitHub Actions build status (cmake cosmo)](https://github.com/ivmai/bdwgc/actions/workflows/cmake-cosmo.yml/badge.svg?event=push)](https://github.com/ivmai/bdwgc/actions/workflows/cmake-cosmo.yml?query=branch%3Amaster)
 [![GitHub Actions build status (zig build/test)](https://github.com/ivmai/bdwgc/actions/workflows/zig-build.yml/badge.svg?event=push)](https://github.com/ivmai/bdwgc/actions/workflows/zig-build.yml?query=branch%3Amaster)
 [![GitHub Actions build status (zig cross-compile)](https://github.com/ivmai/bdwgc/actions/workflows/zig-cross-compile.yml/badge.svg?event=push)](https://github.com/ivmai/bdwgc/actions/workflows/zig-cross-compile.yml?query=branch%3Amaster)
 [![GitHub Actions status (clang-format)](https://github.com/ivmai/bdwgc/actions/workflows/clang-format-check.yml/badge.svg?event=push)](https://github.com/ivmai/bdwgc/actions/workflows/clang-format-check.yml?query=branch%3Amaster)