Fix/add missing aria labels

[nikeeshi]

Types of changes

What types of changes does your code introduce?

Put an x in the boxes that apply

• [x] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description

Added a new feature to let user insert aria-label into several types of elements: the input box to set start date and end date, the drop-down menus to select month and year, the button to change month of calendar.

Related Issue: #373 Related Issue: #415 Related Issue: #416

[kamyar]

@nikeeshi I also added you as a collaborator. Given you have already opened a PR to contribute, in case you would be interested in getting involved more. 🚀 Obviously if you can not allocate time for the project feel free to decline the invite. :)