Bug#898592: lintian: add tag debian-pyversions-is-obsolete

[Joseph Herlant <herlantj@gmail.com>]

Package: lintian
Version: 2.5.86
Severity: wishlist

Dear Maintainer,

Since the transition to dh_python2 [1], it is recommended by the python policy
[2] to use X-Python-Version and X-Python3-Version tag in debian/control (if
necessary) instead of the debian/pyversions file.

I think it would be a good thing to start showing an info-level message like we
did for pycompat to remind people to move to clean this file from the repo.

Joseph

[1] https://wiki.debian.org/Python/TransitionToDHPython2
[2] https://www.debian.org/doc/packaging-manuals/python-policy/ch-module_packages.html#s-specifying_versions