[FIX] get_requirements: add --line_ending argument

[ramiadavid]

I have added the --line_ending argument to avoid differences when running on Windows or Linux, by default Python uses '\n' for Linux and '\r\n' for Windows and this causes problems when running on pre-commit.

Options: cr(\r) | lf(\n) | crlf(\r\n)
Default: lf

[sbidoul]

Thanks for this PR.

Can you elaborate a little bit the problem you are trying to resolve?
Since other tools (such as black, for instance) that modify the code and are run by pre-commit don't typically have that kind of option, I'm not sure we need one here.

[ramiadavid]

When I run pre-commit on windows it creates the requirements.txt (overwriting existing file) with \r\n but when I push to github and run pre-commit are created with \n and then pre-commit tests fail
In other tools you can specify line endings in .editorconfig but here Python does it automatically depending on the operating system

[sbidoul]

Ok. For the sake of simplicity, I think we can use LF unconditionally. If anyone later needs the configurability, it can be added with proper tests and documentation (taking inspiration from pip-tools --newline option, for instance).

Could you make the change, and also add a newsfragments/98.feature with a short changelog entry?

[ramiadavid]

Done