REL: v3.7.3

This is the third bugfix release of the 3.7.x series.

This release contains several bug-fixes and adjustments:

• Add Python 3.12 wheels
• Update the license for the bundled colorbrewer colormap data
• Fix Cairo backend when using cairocffi
• Fix axes_grid1 inset axes with bbox_inches=tight
• Fix bugs in Path3DCollection / Poly3DCollection constructors
• Fix setting array labelcolor on Tick
• Improve compatibility with latest NumPy
• Stop warning when calling tight_layout multiple times