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

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

Start with client.py:546 and client_pull.py:553, then inspect client-log.txt for the GEODIFF extension error. Reproduce the pip-installed Windows workflow described in the issue and trace the GeoPackage pull step. Done means pull_project completes for a changed GeoPackage without the reported ClientError.