Resolve "Migrations fail"

Closes #248

See merge request !336

Update tox.ini

See merge request !337

Update pyproject.toml

See merge request !334

Translations update from Weblate

See merge request AlekSIS/official/AlekSIS-App-Alsijil!320

Currently translated at 100.0% (289 of 289 strings)

Translation: AlekSIS/AlekSIS-App-Alsijil
Translate-URL: https://translate.edugit.org/projects/aleksis/aleksis-app-alsijil/ru/

Prepare release 3.0b0

See merge request !323

Resolve "Re-introduce tab layout on week view"

See merge request !329

Resolve "Custom excuse types aren't counted correctly in generate_person_list_with_class_register_statistics"

See merge request !326

# Conflicts:
#   CHANGELOG.rst

Merge branch '241-two-columns-in-group-statistics-table-are-interchanged' into 'prepare-release-3.0b0'

Resolve "Two columns in group statistics table are interchanged"

See merge request !328

Merge branch '239-property-count_label-of-excusetype-allowing-whitespaces-in-it-breaks-usage-of-it-as-column-alias' into 'prepare-release-3.0b0'

Resolve "Property count_label of ExcuseType and ExtraMark allowing whitespaces in it breaks usage of it as column alias"

See merge request !324

Merge branch 'prepare-release-3.0b0' into '239-property-count_label-of-excusetype-allowing-whitespaces-in-it-breaks-usage-of-it-as-column-alias'

# Conflicts:
#   CHANGELOG.rst

Resolve "Fix PDF generation"

See merge request !325

Resolve "All register objects legacy page is not usable in SPA"

Closes #237

See merge request !321

Translations update from Weblate

See merge request !293