Client fails to pull on windows (when installed from pip)

[wonder-sk]

When using the client on Windows outside of QGIS (e.g. installed through pip), it does not work correctly when trying to pull a new version that involves geodiff operations:

import mergin
client = mergin.MerginClient (login='john', password='topsecret')
client.download_project('john/project', 'C:/Data/Project')
# now do some modifications to a GeoPackage on the server
client.pull_project('C:/Data/Project')

It fails with the following traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\XYZ\AppData\Roaming\Python\Python38\site-packages\mergin\client.py", line 546, in pull_project
    return pull_project_finalize(job)
  File "C:\Users\XYZ\AppData\Roaming\Python\Python38\site-packages\mergin\client_pull.py", line 553, in pull_project_finalize
    raise ClientError("Cannot patch basefile {}! Please try syncing again.".format(basefile))
mergin.common.ClientError: Cannot patch basefile C:\Data\Project\.mergin\test.gpkg! Please try syncing again.

It looks like the underlying issue is in geodiff as client-log.txt contains this error:

GEODIFF: Unable to enable sqlite3/gpkg extensions

[wonder-sk]

It looks like adding sqlite3 module import fixes the issue:

import sqlite3

[PeterPetrik]

could be related also that we shipped sqlite without tree, see MerginMaps/geodiff#167