v1.5.11-rc.1

Full Changelog

• Upgrade to JS SDK 5.1.0-rc.1 and React SDK 2.2.0-rc.1
• Change Windows signing to warning when missing token
  #12523
• Modernizr remove t3st/es6/contains
  #12524
• Switch out any eval-using Modernizr rules
  #12519
• Update from Weblate
  #12522
• Notify electron of language changes
  #12487
• Relax macOS notarisation check to print a warning
  #12503
• Clarify supported tier means desktop OSes
  #12486
• Use noreferrer in addition to noopener for edge case browsers
  #12477
• Document start / end composer shortcuts
  #12466
• Update from Weblate
  #12480
• Remove buildkite pipeline
  #12464
• Remove exec so release script continues
  #12435
• Use Persistent Storage where possible
  #12425