Update MyPy max pinned version to 0.782

[sidmitra]

• The latest version of MyPy is 0.782 here

[sidmitra]

I've been using the latest master with 0.782 for the past few weeks and everything seems to work correctly.

[sidmitra]

Will try to take a look at the CI error later today. Not sure if it's related to the PR.

$ mypy -p rest_framework-stubs
rest_framework-stubs/request.pyi: error: Source file found twice under different module names: 'rest_framework-stubs.request' and 'rest_framework.request'  [misc]
Found 1 error in 1 file (checked 48 source files)
The command "mypy -p rest_framework-stubs" exited with 2.

[sobolevn]

Yes, this is known bug in the latest mypy. That's why I had to pin it to the previous version. See python/mypy#8944

[sidmitra]

@sobolevn Thanks for the link, wasn't aware of that. I didn't come across any issues on our production codebase. I will take a deeper look, looks more involved though.

[Goldziher]

This PR can be closed @sobolevn