Cut release v0.21.0

[pierremtb]

What's Changed

• Sketch light mode by Frank
• Clean up and fixes by Kurt
• Remove backdrop highlight in onboarding by Frank
• Move the command bar out to the right in the AppHeader by Frank

Full Changelog: v0.20.2...v0.21.0

[qa-wolf]

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Name	Status	Preview	Updated (UTC)
modeling-app	✅ Ready (Inspect)	Visit Preview	May 10, 2024 9:00am

[pierremtb]

macOS build tests:

• sign in
• open existing project
• create new project
  • sketch on base plane
  • rectangle 100x100
  • create variable for width
  • extrude to variable
  • sketch on top face
  • rectangle
  • create margin variable and use it
  • extrude to variabl
  • export to STL ascii
  • change project settings
• sign out
• sign back in

Noticed we're seeing part of edges that we shouldn't sometimes:

[pierremtb]

Win10 build tests:

• sign in
• open existing project
• create new project
  • sketch on base plane
  • rectangle
  • extrude
  • sketch on top face
  • rectangle
  • extrude
  • export to STL ascii
  • change project settings
• sign out
• sign back in