add climpred to climate list

[bradyrx]

Project name: climpred

Project website/repository: https://climpred.readthedocs.io

License: MIT

Checklist for new projects:

• [X] The project is open-source and accessible.
• [X] Searched the existing entries to make sure this is not a duplicate.
• [X] Contains only a single addition (make separate PRs if adding more than one).
• [X] Added the link to the bottom of the relevant category.
• [X] Add icon from the media/icon/ folder if applicable (like ![Python](media/icon/python.png) ).
• [X] Created a new category only if necessary.
• [X] Checked spelling and grammar.
• [X] Removed trailing whitespace and periods.
• [X] Confirm the dash – is not a minus -.
• [X] Used title-casing (AP style) for project name.

[jhamman]

Thanks @bradyrx!