It seems like Mergify doesn't pick up success status of our GitHub
Actions. Looking at the doc
https://docs.mergify.com/conditions/#github-action, the conditions rule
should be `check-success`, but we have `status-success`.
* ci: mergify: remove Codacy from required checks
It might be hanging, and is not really valuable enough currently to
require a rebuild etc.
* ci: mergify: rename check for Travis CI
It was moved from travis-ci.org to travis-ci.com.
It has the drawback of having intermediate merge commits for when
Mergify merges master before because of this, and then does not
squash-merge or rebases it when merging.
