Add Bengali Authornamespace [100] in wikisource_family.py
Add Bengali Authornamespace [100] in wikisource_family.py

Bug: T186341
Change-Id: I2e6b216d37b3be2bc377cc5953f4d0e9fe671281

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