v1.1.1

Updates:

• Tweak grouping flattening methods (#46)

Developer updates:

• Use vMAJOR GH Actions where appliccable (#44)
• Update pre-commit hooks (#20, #28, #32, #37, #44)
• Update development dependencies (#20, #28, #32, #39, #40, #44):
  • invoke~=1.6
  • pre-commit~=2.15
  • pylint~=2.11