Missing polish language in qalendar

[bendarmultimedia]

Checklist

Please put "X" in the below checkboxes that apply::

• If committing a bugfix, I have tested it in different browsers (Chrome, Firefox, Safari).
• If committing a new feature, I have first submitted an issue (Please note: you are free to open PRs for non-issued features, but opening an issue increases your chance of a successful PR).
• If committing a new feature, I have also written an appropriate test suite for it.

I have tested the following:

• Qalendar component in month mode.
• Qalendar component in week mode.
• Qalendar component in day mode.
• All of the above modes on emulated mobile view.
• Dragging and dropping events.
• Resizing events in day/week modes.
• Clicking events to open event dialog.

This PR solves the following problem**.

insert your description.

How to test this PR**.

For example:

1. Feed X and Y in the events-Prop.
2. Click Z or A.
3. Confirm that B is displayed.

[coveralls]

coverage: 97.335% (-0.3%) from 97.603%
when pulling d20226a on bendarmultimedia:master
into db1f199 on tomosterlund:master.

[felix-berlin]

🎉 This PR is included in version 3.8.0 🎉

The release is available on:

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

Your semantic-release bot 📦🚀