Support `FormData` Node.js v18

Since Node.js v18, FormData is part of the native Node.js’ API:

Unfortunately mailgun.js doesn’t support it yet. Furthermore the recommended form-data library is unmaintained and not a good alternative.

[olexandr-mazepa]

Hi RemyMachado Currently, Axios isn’t compatible with FormData implemented in node 18. I don’t want to switch to another package because I believe this issue will be fixed in Axios soon.

Here is a related issue in the Axios library that may be used for tracking: https://github.com/axios/axios/issues/5327

[olexandr-mazepa]

There are a few reasons:

• First one. Fetch API was added to the node.js started only from v17(experimental support). I still have been trying to make this package available from node 12.
• The second one is this comparison article https://www.geeksforgeeks.org/difference-between-fetch-and-axios-js-for-making-http-requests/ . A few items from the table at the bottom are bothering me(built-in XSRF protection, name of body property, stringifying of a data object, canceling the request, etc.).
• The third one is that I recently moved from ky to Axios, and don’t want to repeat this experience =)

Of course, they won’t stop me if node 18 support in Axios takes too much time but in this particular case, I would rather wait some time. Axios will need to implement compatibility with node 18 anyway, and it seems there is a PR already that should fix the issue with form data.