Update fonttools to 4.51.0

[pyup-bot]

This PR updates FontTools[ufo,lxml,unicode] from 4.48.1 to 4.51.0.

Changelog

4.51.0

----------------------------

- [ttLib] Optimization on loading aux fields (3464).
- [ttFont] Add reorderGlyphs (3468).

4.50.0

----------------------------

- [pens] Added decomposing filter pens that draw components as regular contours (3460).
- [instancer] Drop explicit no-op axes from TupleVariations (3457).
- [cu2qu/ufo] Return set of modified glyph names from fonts_to_quadratic (3456).

4.49.0

----------------------------

- [otlLib] Add API for building ``MATH`` table (3446)

Links

• PyPI: https://pypi.org/project/fonttools
• Changelog: https://data.safetycli.com/changelogs/fonttools/
• Repo: http://github.com/fonttools/fonttools

[pyup-bot]

Closing this in favor of #729