[CLI] Force `dump_lines()` to always use Unix line endings

[fauxpark]

Description

When running ./util/regen.sh on Windows, every file generated (using dump_lines()) gets its newlines changed from LF to CRLF regardless of if there are any substantial changes to them. Since we enforce LF through Git anyway, this shouldn't really affect anything but we can turn off this noise by telling write_text() to use LF all the time.

Types of Changes

• [ ] Core
• [x] Bugfix
• [ ] New feature
• [ ] Enhancement/optimization
• [ ] Keyboard (addition or update)
• [ ] Keymap/layout/userspace (addition or update)
• [ ] Documentation

Issues Fixed or Closed by This PR

Checklist

• [x] My code follows the code style of this project: C, Python
• [x] I have read the PR Checklist document and have made the appropriate changes.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[fauxpark]

TypeError: write_text() got an unexpected keyword argument 'newline'

Hm, seems to have been added in Python 3.10...