Bug#937831: python-imaplib2: Python2 removal in sid/bullseye

[Ilias Tsitsimpis]

Control: usertag -1 + py2keep
Control: forwarded -1 https://github.com/imaplib2/imaplib2/issues/7

This package is dead upstream, but is needed by OfflineIMAP, which has
been tagged as `py2keep`, so I am tagging this package as well.

Best,

-- 
Ilias