v1.1.0

This release removes BA-to-BA hurdle rates from the model. Configuration
files written for v1.0.0 must drop the ba_to_ba_hurdle_scaled_file and
ba_to_ba_transmission_matrix_file keys.

Added

• Must-run (nuclear) output in mwh_file. Each bus with must-run capacity
  is reported as <bus>_NUCLEAR with Type=Nuclear, using the
  outage-adjusted must-run capacity for every hour.
• Documentation website built with Sphinx and the PyData theme, published
  to GitHub Pages at https://immm-sfa.github.io/gridops. It covers getting
  started, a rendered quickstarter notebook, a user guide (configuration,
  inputs, outputs, mathematical formulation, simulation and solvers), the
  API reference, contributing guidelines, publications, how to cite, release
  notes, publications, authors, license and acknowledgement.
• GitHub Actions docs workflow that builds the documentation on pull
  requests and deploys it to the gh-pages branch on every push to main.
• Documentation of the warmstart option in the Model and Model.run
  docstrings.
• PyPI and docs badges in the README.

Changed

• Fixed the sign convention of the example line_to_bus.csv so that each
  line has +1 at its from bus and -1 at its to bus; positive flow now
  runs from the from bus to the to bus. The example outputs were
  regenerated.
• Clarified the power-flow sign convention in the bus balance constraint.
• Updated the quickstarter notebook for the removed hurdle rates and the new
  nuclear output.
• Replaced the docs extra (nbsphinx, sphinx-panels, sphinx-rtd-theme,
  setuptools) with sphinx, pydata-sphinx-theme, sphinx-design,
  sphinx-copybutton and myst-nb.
• Reworded the README and noted that HiGHS installs with the highspy
  dependency.

Removed

• BA-to-BA hurdle rates: the ba_to_ba_hurdle_scaled_file and
  ba_to_ba_transmission_matrix_file configuration keys, the exchanges
  set, the ExchangeHurdle and ExchangeMap parameters, the exchange cost
  term in the objective, and the example files
  BA_to_BA_hurdle_scaled.csv and BA_to_BA_transmission_matrix.csv.