Update the code coverage badge with the latest recommended
markdown from coveralls.io
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
[](https://travis-ci.org/libcgroup/libcgroup)
-[](https://coveralls.io/github/libcgroup/libcgroup?branch=master)
+[](https://coveralls.io/github/libcgroup/libcgroup?branch=master)
The entire libcgroup README is available [here](README).