Accessibility issue - selected month is not announced by screen reader

[Ke1sy]

Describe the bug
When you change month, it is expected that the new month with year will be announced by screen reader.
Currently after clicking next/prev month button, user doesn’t know that month has changed and what month is currently selected, because nothing is announced. It is recommended to add aria-live="polite" and announce changed information to user.

To Reproduce

1. Start the screen reader and open the date-picker with keyboard.
2. Navigate to previous or next month button, then click it

Expected behavior
Selected month with year will be announced by screen reader.

Desktop (please complete the following information):

• OS: [e.g. iOS] Windows 10
• Browser: Chrome (v. 100.0.4896.75), Firefox

[martijnrusschen]

fixed by #3817