http-request-action: File Uploads with `\` in the path are broken

Hi @fjogeleit, thanks a lot for this excellent action. I’m using in in quite a few projects.

I just spent about an hour trying to figure out why my file was not uploaded. Turns out that this action does not seem to like Windows-style filepaths (with \) like they are generated by path.join(...) in JS. When I replace them with forward slashes, everything works as expected.

For example:

files: { "file": "D:/a/myApp/myApp/release/My-App-win32-x64-1.0.0.exe" }

works, but

files: { "file": "D:\a\myApp\myApp\release\My-App-win32-x64-1.0.0.exe" }

does not.