python3-pygments: upgrade 2.14.0 -> 2.15.1

* Upstream has dropped setup.py
* Inherit python_setuptools_build_meta instead of setuptools3
* Add self as maintainer, as this is a dependency for python3-sphinx

Adds some new lexers, updates a few others. A handful of bug fixes.

https://github.com/pygments/pygments/blob/2.15.1/CHANGES#L6
https://github.com/pygments/pygments/blob/2.15.1/CHANGES#L18



Signed-off-by: Tim Orling <tim.orling@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>