Dropping Python 3.5 support

[Avasam]

Can dropping support for Python 3.4 and 3.5 be considered ? Here's the two main reasons:

1. No more Pillow security concerns. That section can be removed from the readme:

NOTE - PyScreeze depends on Pillow for screenshots, whose older versions have security issues. The only secure versions of Pillow are 8.3.2 and later. However, Pillow 8.3.2 only supports Python as far back as Python 3.6. If you are installing PyScreeze for Python 3.5 or earlier, be aware that there may be security issues with the version of Pillow it uses.

2. Greatly simplifying Type hints and type comments #84