Update URL references

[scottlee]

Description of the Change

The links to eslint and babel-preset were pointing at archived repos. This PR updates these links.

• Update eslint link to: https://github.com/10up/10up-toolkit/tree/develop/packages/eslint-config
• Update babel-preset to: https://github.com/10up/10up-toolkit/tree/develop/packages/babel-preset-default

How to test the Change

Review .md file.

Changelog Entry

Fixed - References to archived repos.

Credits

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.