feat: add version check to installer and plugin script

[mrcjkb]

The neovim version requirement in the readme can be overlooked, leading to people opening issues.

[github-actions[bot]]

Review Checklist

Does this PR follow the Contribution Guidelines? Following is a partial checklist:

Proper conventional commit scoping:

• For example, fix(installer): some installer bugfix

• [x] Pull request title has the appropriate conventional commit prefix.

If applicable:

• [x] Tested
  • [ ] Tests have been added.
  • [x] Tested manually (steps in PR description).
• [ ] Updated documentation.

[mrcjkb]

This isn't working on Windows. Weird...