Remove irrelevant dependency on the module `typing`

[moste00]

This module started being included in Python from version 3.5, its PyPI page (https://pypi.org/project/typing/) explicitly says that installing it in any Python from 3.5 onwards has 0 effects. The reason this dependency is annoying is - in addition to cluttering the requirements.txt - it makes Pyinstaller choke and fail for some reason. We rely on Pyinstaller in the CI to produce the static binaries we publish to the Releases. The temporary workaround to this that the CI currently makes is running pip uninstall -y typing before invoking Pyinstaller, but this is an ugly and unnecessary hack.

The PR that will close this issue will:

• Remove typing from requirements.txt
• Ensure that neither the dev experience nor the user experience has degraded
• Modify the CI files to remove the pip uninstall