Fix flake8 command (which checks all *.py files anyway)
Fix flake8 command (which checks all *.py files anyway)

https://travis-ci.org/github/agt-the-walker/shogi-utils/jobs/677791115

$ flake8 *.py
The command "flake8 *.py" exited with 0.

I don't know if Travis CI performs wildcard expansion though. OTOH:

$ flake8 -v 2>&1 | grep -w Checking
flake8.checker            MainProcess     85 INFO     Checking 3 files
$

agt-the-walker/shogi-utils,agt-the-walker/shogi-utils