Replacing pysftp with sftpretty (maintained fork of pysftp)

[MadsHangaard]

Changelog Description

• Resolves ImportERROR on SiteSync start when using SFTP provider.
• Removes dependency: pysftp
• Adds dependency: sftpretty

resolve #17

Additional review information

pysftp throws and error when imported, as it imports features from paramiko that has been removed due to deprecation. pysftp is an unmaintained library. This PR replaces pysftp with sftpretty which is a maintained fork of pysftp.

Testing notes:

1. Update package
2. Update dependency
3. Add site with SFTP provider to ayon+settings://sitesync
4. Launch Ayon launcher, no ImportERROR should appear
5. Download & Upload via SiteSync SFTP Provider

[iLLiCiTiT]

Suggested change

	import sftpretty
	import paramiko
	sftpretty= None
	try:
	import sftpretty
	import paramiko
	except (ImportError, SyntaxError):
	pass

[MadsHangaard]

Hey Jakub, thanks for taking a look at it. I'm not super familiar with the PR process. Should I add this suggestion to my PR? Or will you guys add it, in the review process? :)

[iLLiCiTiT]

HI, thanks for the PR.

Yes, you have to add the suggestions in your branch so it is part of the PR. You can either do local changes and push them or with "suggestion" comments you can just use the Commit suggestion button (if you agree with the changes, to fultill the review process).

[MadsHangaard]

I removed this part, as I didn't quite understand the utility of not failing immediately, only to fail later. Would you mind explaining the thought process behind it?

Furthermore, I removed this part:

if not pysftp:
    raise ImportError

Which should probably be re-added with sftpretty. In case of adding the try/except block on import.

if not sftpretty:
    raise ImportError