One of the projects I manage with CodeClimate uses a checkstyle configuration that's incompatible with versions <8.24. I just tried to enable CodeClimate's Checkstyle plugin and found it didn't work with my configuration, so I went to upgrade the support.

This diff fixes the upgrade script to find the latest version of checkstyle's jar file (moved from sourceforge to github). It also applies the upgrade and fixes up a few things in the default configuration that are no longer compatible with versions of Checkstyle >=8.24. Now all the tests pass cleanly.