[joinrpg-docs-253] add linter info to readme

Author: avs51

README.md

@@ -2,5 +2,8 @@
 
 [![Documentation Status](https://readthedocs.org/projects/joinrpg/badge/?version=latest)](http://joinrpg.readthedocs.io/ru/latest/?badge=latest)
 
+Linter warnings and errors:
+Actions - Build sphinx docs job - Build static files step
+
 In this repository we have documentation for joinrpg. See http://docs.joinrpg.ru.
 Maintainers: @tsareva, @dtrub