py-scikit-build: updated to 0.17.6

Scikit-build 0.17.6
===================

A small fix release with some new platforms and better testing, including CPython 3.12.0b1.

Bug fixes
---------
* Support added for SunOS by :user:`mtelka`
* Support added for AIX (with recent CMake) by :user:`bhuntsman`

Testing
-------
* Tests now pass on CPython 3.12.0b1
* Tests no longer use ``pytest-virtualenv``
* ``isolated`` marker now includes ``test_distribution`` tests
* Tests avoid incorrect ``get_map`` match by :user:`keszybz`
* Fedora testing fix by :user:`LecrisUT`

Miscellaneous
-------------
* Docs improvements

(adam)