🚀 Improve handling of unchanged files

Previously, unchanged files were added to ESLint's ignore-list, which worked fine until all files were ignored, which would cause ESLint to throw a warning.
This is now removed and instead, the unchanged files are excluded from being linted using ESLint's preprocessor.
The removal of ignorePatterns also opens up the possibility of using this plugin with older versions of ESLint in future releases.