Closes # (if applicable).

Changes proposed in this Pull Request

Currently, there is a bug in the retrieval of LAU region data for the computation of geothermal heat potentials (incorrectly downloading a zip and renaming it to geojson rather than unpacking it). This bug was not noticed because geothermal heating is turned off by default.

This PR fixes the data retrieval. Note that there seems to be a remaining bug related to the efficiency2 handling in perfect foresight.

Checklist

• I tested my contribution locally and it works as intended.
• Code and workflow changes are sufficiently documented.
• Changed dependencies are added to envs/environment.yaml.
• Changes in configuration options are added in config/config.default.yaml.
• Changes in configuration options are documented in doc/configtables/*.csv.
• Sources of newly added data are documented in doc/data_sources.rst.
• A release note doc/release_notes.rst is added.