v0.19.0

Updates:

• Moved to the latest optimade, v0.16.3 (#282).
  This introduced extra validations, leading to a fix of the calculation of the chemical_formula_anonymous field.
• Moved to the latest AiiDA version, 1.6.5 (#274).

Developer updates:

• Updated dependencies (#270, #274, #277, #282):
  • pre-commit~=2.15
  • uvicorn~=0.15.0
  • pylint~=2.10
• Update various GH Actions.