feat(locales): add Czech locale

[arthurdenner]

What kind of change does this PR introduce?
Feature. Replaces #206.

What is the current behavior?
No Czech locale available.

What is the new behavior?
New locale is available under key cs-CZ.

Checklist:

• Documentation
• Tests
• Ready to be merged

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[codecov]

Codecov Report

Merging #268 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #268   +/-   ##
========================================
  Coverage    87.25%   87.25%           
========================================
  Files           14       14           
  Lines          463      463           
  Branches        92       92           
========================================
  Hits           404      404           
  Misses          56       56           
  Partials         3        3           

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[knuhol]

Texts are correct

Note: Not sure in which context it is used (if it is supposed to be a title or not) but in general all weekdays and months in Czech language start with lower case

[arthurdenner]

🎉 This PR is included in version 2.6.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀