Bump to Matplotlib 3.7.1

[QuLogic]

And also Cartopy to latest version to make it installable on current versions of Python.

Fixes #116
Fixes #124

[QuLogic]

Possible things to investigate after finishing the build locally:

• Beginners:
  • Edges around scatter, bar, pie, hist, and boxplot are not exactly the same size
• Intermediate:
  • Edges around anatomy circles are missing
  • Sine and Cosine figure appears to be a bit taller
• Tips:
  • Random data in transparency section seems completely different

Some similar problems occur in the 2-page version.

[QuLogic]

Also note that the anatomy example has changed somewhat in Matplotlib: https://github.com/matplotlib/matplotlib/compare/v3.5.0..v3.7.1#diff-d476362ab30b16055b90f54100d51a2d0e479f1f886bbf371f2008f734bb9ef8; not sure if we want to bring those changes over here.

[QuLogic]

Looking at the results from the build:

• On cheatsheets p1, seaborn-notebook -> seaborn-v0_8-notebook is a little too wide, but still visible.
• On cheatsheets p2, the Axes in the imshow example, Image Interpolation section, and Annotation connection styles section are now compressed closer.
• On the intermediate handout, there are minor shifts because the Sine and Cosine figure is a little bit taller.
• On the tips-and-tricks handout, the random results in the Transparency section have changed; it doesn't appear to have a seed.

Please ignore all my previous comments about local differences, as they appear to be local to my machine and not specific to this change.

[QuLogic]

Also, looking at the build a bit closer, it appears that figures/legend.pdf changed because it was re-cropped, but that's not a real change, so I will revert that.

[QuLogic]

With #126 in, the tip-and-tricks diff is now:

[QuLogic]

IIRC, we stopped counting invisible ticks in tight layout at some point, which is likely the reason the Axes were clipped closer, and thus appear a bit bigger now.

[QuLogic]

Rebased, but note the above comment: #125 (comment)

[timhoffm]

Rebased, but note the above comment: #125 (comment)

Theoretically yes. But that doesn't have to be within this PR. And please check whether it's still readable - if I see it correctly, we have added more content.