Describe the bug
If you have a mutation that uploads file(s), successfully within Altair when you choose "copy as curl" a curl command line is generated but when you run it in curl it does not upload the files.

To Reproduce
Steps to reproduce the behavior:

1. Create a graphql service that accepts uploads.
2. Create an Altair client mutation, variables and upload file(s)
3. Check that it works in Altair, and your server is getting the files.
4. click on "Copy to Curl"
5. Open an bash window and paste to the command line.
6. Observe that the command line contains no references to the upload files that you have set.
7. Run the command line and see that your server does not receive any files.
   Expected behavior
   I expect the "save as curl" command line should behave exactly as Altair does, if it knows where the files are.

Desktop (please complete the following information):

• OS: Ubuntu hippo 21.04
• Browser chrome Version 91.0.4472.77 (Official Build) (64-bit)
• Platform: Chrome extension and snap
• Version Not sure (about does not work) downloaded yesterday.

Additional context
Add any other context about the problem here.