The master branch was renamed to main, but the build status
badge wasn't updated as part of this change. Display the
build status of the main branch in README.md
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
-[](https://github.com/libcgroup/libcgroup/actions)
+[](https://github.com/libcgroup/libcgroup/actions)
[](https://coveralls.io/github/libcgroup/libcgroup)
The entire libcgroup README is available [here](README).