Test ci on mac

[davide-f]

Closes #316

Changes proposed in this Pull Request

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Newly introduced dependencies are added to envs/environment.yaml and envs/environment.docs.yaml.
• Changes in configuration options are added in all of config.default.yaml, config.tutorial.yaml, and test/config.test1.yaml.
• Changes in configuration options are also documented in doc/configtables/*.csv and line references are adjusted in doc/configuration.rst and doc/tutorial.rst.
• A note for the release notes doc/release_notes.rst is amended in the format of previous release notes, including reference to the requested PR.

[davide-f]

The CI on windows is breaking because of this issue: conda-forge/fiona-feedstock#192
Once that issue is fixed, all CIs should be working.

[davide-f]

The new release of fiona (1.8.21) makes the CI break.
Therefore, in this PR fiona is limited to 1.8.20 till Toblerity/Fiona#1085 is solved.
Moreover, old limits to package versions (es dask) in the environment have been removed, as no more needed.