Add CHANGELOG.md [ci skip]
Add CHANGELOG.md [ci skip]

Release descriptions on GitHub don't seem to be a part of the repo.
Migrate them into a file.

xpol/luacheck,xpol/luacheck,linuxmaniac/luacheck,xpol/luacheck,mpeterv/luacheck,mpeterv/luacheck,linuxmaniac/luacheck,mpeterv/luacheck