MiniZinc Python 0.3.0

Added

• Add support for different MiniZinc compiler optimisation levels. All methods that
  compile an instance now have an additional optimisation_level argument.

Changed

• The DZN parser functionality has been moved into the dzn extra. If your
  application requires parsed dzn information, then you have to ensure your
  MiniZinc Python is installed with this extra enabled:
  pip install minizinc[dzn].
• Solver has been turned into a dataclass and has been updated with all
  attributes used in the compiler.

Fixed

• Resolve relative paths when directly loading a solver configuration. This
  ensures that when a temporary solver configuration is created, the paths are
  correct.