Use new change tracker from Chronos

See merge request !127

Resolve "Lesson periods are deleted and then cause data problems"

Closes #47

See merge request !131

Resolve "Fuzzy matching of course groups"

Closes #46

See merge request AlekSIS/official/AlekSIS-App-Untis!129

Resolve "Take teachers into account when matching course groups"

Closes #45

See merge request !128

Merge branch '45-take-teachers-into-account-when-matching-course-groups' into 46-fuzzy-matching-of-course-groups

Update dev dependencies

See merge request !130

Release 2.1.3

See merge request !126

Let management command default to current

See merge request !124

Resolve "Ignore incomplete substitutions feature is incomplete"

Closes #42

See merge request !123

Release 2.1.2

See merge request !121

Translations update from Weblate

See merge request !116

Currently translated at 100.0% (26 of 26 strings)

Translation: AlekSIS/AlekSIS-App-Untis
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-untis/de/

Update translation files

See merge request !122