py-fonttools: updated to 3.39.0

3.39.0:
- [ttLib/glyf] Raise more specific error when encountering recursive
  component references.
- [Doc/designspaceLib] Defined new public.skipExportGlyphs lib key.
- [varLib] Use vmtx to compute vertical phantom points; or hhea.ascent
  and head.unitsPerEM if vmtx is missing.
- [gvar/cvar] Sort XML element's min/value/max attributes in TupleVariation
  toXML to improve readability of TTX dump.
- [varLib.plot] Added support for 2D plots with only 1 variation axis.
- [designspaceLib] Use axes maps when normalizing locations in
  DesignSpaceDocument, and when finding default source.
- [mutator] Set OVERLAP_SIMPLE and OVERLAP_COMPOUND glyf flags by
  default in instantiateVariableFont. Added --no-overlap cli option
  to disable this.
- [subset] Fixed subsetting VVAR table.
  Fixed subsetting an HVAR table that has an AdvanceWidthMap when the
  option --retain-gids is used.
- [feaLib] Added forceChained in MultipleSubstStatement.
  Fixed double indentation of subtable statement.
  Added support for subtable statement in more places than just PairPos
  lookups.
  Handle lookupflag 0 and lookupflag without a value.
- [varLib] In load_designspace, provide a default English name for the
  ital axis tag.
- Remove pyftinspect because it is unmaintained and bitrotted.

(adam)