Slack's files.upload method is being deprecated

[delenamalan]

📣 Notification Service(s) Impacted
Slack

🐞 Describe the bug
The Slack files.upload method used here is being deprecated. As of May 16th, it already does not work for newly created apps.

files.upload usages need to be replaced by files.getUploadURLExternal and files.completeUploadExternal.

💡 Screenshots and Logs
I'm getting this error for a newly created bot:

2024-05-19 13:32:26,132 - DEBUG - Response Details:
b'{"ok":false,"error":"method_deprecated"}'

💻 Your System Details:

• OS: Mac OS 14.5
• Python Version: 3.11.5

🔮 Additional context

[caronc]

Great find and thank you for reporting this! 🙏 I noticed you also cloned the repository. Are you doing a PR for this?

[delenamalan]

Hey @caronc, yes, I'm working on a PR for this. :)