pypa:pywwt 0.21.0

pypa:pywwt 0.21.0 (2023-07-28)

• Update pywwt to work with version 7 of the Jupyter notebook package (#356,
  @Carifio24, @pkgw). This new version is a major update on the Jupyter side,
  but it is only used in a few minor places within pywwt. The pywwt package
  should remain compatible with older versions of notebook.
• Fix pywwt’s default ecliptic grid color to match the engine (#356,
  @Carifio24).