feat: add support for configuing a default local repository path

[markfeinstein]

Summary

Add fallback logic to the GetRepoLocalPath to allow a default_path to be configured to handle repository paths that aren't explicitly configured.

Additional changes:

• Update deps
• Add testify module
• Refactor repo path unit test to use table tests

How did you test this change?

• Ran unit tests
• Local testing with a repo that doeos not have a matching or wildcard definition in gh-dash
  • Perform a checkout of a pr
  • Open a pr in Octo.nvim

[dlvhdr]

Thank you! I'll take a look later this week