v3.1

Update Summary

• [NEW] Precipitation distribution and bimodality metric
• Technical minor patches for mean climate including more flexibility in file opening, graphics, and output JSONs (add more metadata information)
• Github CI Build process updated by @tomvothecoder

What's Changed

• Merge branches by @lee1043 in #914
• Merge branches by @lee1043 in #915
• update by @lee1043 in #916
• use autoflake8 and black to apply pep8 code style by @lee1043 in #919
• Update setup.py by @lee1043 in #918
• Mean clim patch by @lee1043 in #920
• 868 msa precip distribution bimodality by @msahn in #913
• Open multiple files using xcdat by @lee1043 in #926

Full Changelog: v3.0.2...v3.1