[tests] update pydocstyle and flake8-docstrings dependency
[tests] update pydocstyle and flake8-docstrings dependency

flake8-docstrings bug is solved upstream with v1.3.1

Bug: T227403
Change-Id: Iecb67d7b996149b9594ad44c016098217a3719fd

PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core