Ktlint check pre-commit hook includes unstaged changes

[Kantis]

Reproduction:

1. Add an unused import to a file
2. Stage the file and try to commit -> precommit hook will fail the commit
3. Remove the import
4. Without staging the file, try to commit -> commit will be allowed with unused import being commited

Behaviour is inconsistent with manually running ./gradlew ktlintCheck while having unstaged fixes, which will correctly complain about the unused import.

[Kantis]

Could probably be solved similar to #470

[KotlinIsland]

This is exactly the issue that was fixed in #470.

[Kantis]

Thanks for the info @KotlinIsland! 10.1.0 came out after the issue was created and I haven't gotten around to testing it. Thanks for fixing it 👍🏼