Invalidate .jupyter-ystore.db if using a different version of jupyter-collaboration

[martinRenou]

Description

Updating jupyter-collaboration from one version to another usually breaks because of .jupyter-ystore.db, removing that file fixes it.

Should we include the current jupyter-collaboration version in this file and have some logic to compare the current version to the version saved in the file? In case of mismatch, the file should be removed.

[davidbrochart]

We already do here.
I would need:

• a test that shows this code doesn't work.
• a fix that passes the fix above.

[andrii-i]

I can reliably and easily reproduce db migration failure in #390 (comment) when updating from jupyter-collaboration v2 to jupyter-collaboration v3. I have a theory on why that happens but wasn't able to prove it yet.

[Zsailer]

I've seen the same issue migrating from v2 -> v3. Will try to create a test when I get some time too.