Fix storage discover signature mismatch

[erik777]

Use this:

Fix Radicale 3.3 storage discover signature mismatch

This updates Storage.discover() in radicale_storage_decsync to accept and forward the additional user_groups argument expected by newer Radicale versions.

Problem:

• with Radicale 3.3.x, the web/discovery path triggers PROPFIND /
• Radicale calls the storage plugin’s discover() with an extra argument
• the current plugin signature does not accept it
• result: Storage.discover() takes from 2 to 4 positional arguments but 5 were given

Change:

• add user_groups to Storage.discover()
• pass user_groups through to super().discover(...)

Why this change:

• fixes the web login/discovery failure on newer Radicale
• preserves existing DecSync write behavior
• avoids unrelated dependency changes

Validation:

• web login to /.web/ succeeds after this patch
• Evolution calendar save still works after this patch

source: #34

[DiagonalArg]

@erik777 / If you want to look over my attempts to keep this plugin up to date, that would certainly be appreciated. This is my PR, but since 39aldo39 seems to be gone, I have just made a release on my repo:

#40

https://github.com/DiagonalArg/Radicale-DecSync