Create branches for different MediaWiki releases.
The CategoryWatch extension depends on the following core functions from MediaWiki. Those functions has changed along with the major releases.
- Message APIs has been used to prepare the message for notification email. Most of the legacy (deprecated) message functions have been removed since version 1.27. Details on page: https://www.mediawiki.org/wiki/Manual:Messages_API#Help_with_replacing_deprecated_wfMsg.2A_functions
- Hook change: ArticleSave -> PageContentSave, the legacy one was removed in version 1.29.0
- Hook change: ArticleSaveComplete -> PageContentSaveComplete the legacy one was removed in version 1.29.0
- The extension.json based Extension registration has started since version 1.25
We should create branches to reflect those major release.