Bump open-autonomy@0.13.8

[angrybayblade]

Proposed changes

This PR

• Updates the mkdocs.yml to remove the usage of a deprecated plugin
• Bumps open-aea@1.42.0, open-autonomy@0.13.8 and tomte@0.2.15

Fixes

If it fixes a bug or resolves a feature request, be sure to link to that issue.

Types of changes

What types of changes does your code introduce? (A breaking change is a fix or feature that would cause existing functionality and APIs to not work as expected.)
Put an x in the box that applies

• Non-breaking fix (non-breaking change which fixes an issue)
• Breaking fix (breaking change which fixes an issue)
• Non-breaking feature (non-breaking change which adds functionality)
• Breaking feature (breaking change which adds functionality)
• Refactor (non-breaking change which changes implementation)
• Messy (mixture of the above - requires explanation!)

Checklist

Put an x in the boxes that apply.

• I have read the CONTRIBUTING doc
• I am making a pull request against the main branch (left side). Also you should start your branch off our main.
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have locally run services that could be impacted and they do not present failures derived from my changes

[dvilelaf]

LGTM. Some linter failures.