* get rid of pattern dependency

* get rid of six import in mmreader.pyx

* bump cython version to 0.29.21

Trying to work around "has no attribute '__reduce_cython__'" problem

* add six to list of dependencies

Why was it removed? Parts of the code still need it.

* rm removed file from docs

* Revert "add six to list of dependencies"

This reverts commit 4e5281431c72126be0e0b4c22d21d54d55205854.

* remove unused six import

* add friendly message

* update gitignore to include cython output

* update gitignore

* fix build

* Update docs/src/scripts/make_wiki_online.rst

* more friendliness

* Update gensim/scripts/segment_wiki.py

* Update gensim/scripts/segment_wiki.py

* skip broken tests

* flake8 fix

* Update CHANGELOG.md

Co-authored-by: Radim Řehůřek <radimrehurek@seznam.cz>