Adding sunsetting info to README in favor GreycLab reimplementation

#87 readme typo

#71 retargetting URLs to current most vivid gmic-py repositories(2)

#71 retargetting URLs to current most vivid gmic-py repositories

#71 retriggering doc build(2)

#71 retriggering doc build

#71 #43 #45 auto-version in docs/ conf

#71 unshortened release version

#71 updated changelog for 2.9.4 alpha1

#71 disabling tests for alpha1

#71 releasing v2.9.4 alpha 1

#83 tutorials: replacing _document_gmic with 2.9.4 alternative

#71 reenabling tests for 2.9.4 in Github Actions

#71 fixed build by tuning gmic::run() call parameters

#71 starting 2.9.4 build