Pynauty

- updated to nauty2_8_8
- decreased space leak by merging PR 40

**Full Changelog**: https://github.com/pdobsan/pynauty/compare/pynauty-1.1.2...v2.8.6

Changes in version 1.1.2 + nauty27r4

- nauty27r4
- added python 3.10.5 to build and test matrix

Changes in version 1.1.1 + nauty27r3

- Added the missing nauty source to the package uploaded to PyPi.

Changes in version 1.1.0 + nauty27r3

- Frank Bryce fixed the issue of accepting multigraphs but then silently ignoring multiple edges when passing to nauty.
- Built with nauty27r3
- Pynauty 1.1.0 works with Python 3.7-3.10 and nauty27r1.

New function `canon_label(g)` to find the canonical labeling of vertices.