Fsrs-optimizer

What's Changed
* Feat/add ICI and related metrics by L-M-Sherlock in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/76


**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.8...v4.21.0

What's Changed
* Fix/drop nan in formula_analysis by L-M-Sherlock in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/75


**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.7...v4.20.8

What's Changed
* Fix/export remove outliers by L-M-Sherlock in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/74


**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.6...v4.20.7

What's Changed
* Fix/improve filter by L-M-Sherlock in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/73


**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.5...v4.20.6

What's Changed
* Fix/deal with bad cases by L-M-Sherlock in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/72


**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.4...v4.20.5

What's Changed
* Fix/Don't remove rows with mean R = 1 by user1823 in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/70

New Contributors
* user1823 made their first contribution in https://github.com/open-spaced-repetition/fsrs-optimizer/pull/70

**Full Changelog**: https://github.com/open-spaced-repetition/fsrs-optimizer/compare/v4.20.3...v4.20.4