fix timezone error (#34)

* fix timezone error

通过更换时区表达模块修复错误 can not import UTC
Fix error can not import UTC by using timezone.utc

* fix format

* bump version

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Co-authored-by: T2XX <[email protected]>
Co-authored-by: Jarrett Ye <[email protected]>

make Card objects JSON serializable (#33)

v2.0.0 - update cards to be timezone aware (#31)

Feat/update to FSRS-4.5 (#22)

* Feat/update to FSRS-4.5

* update minor version

Feat/calc SInc based on last D (#19)

Fix/lapse count of cards (#18)

Fix/wrong elapsed days in ReviewLog (#16)

Feat/FSRSv4 (#13)

fix: typo `State.New_interval` (#12)

* fix: typo

* update version

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Co-authored-by: Jarrett Ye <[email protected]>

Fix/wrong easy interval when review (#11)