Fails to start with Python 3.10

[thorus90]

If you are using python 3.10 the webui fails to start with:

ImportError: cannot import name 'MutableMapping' from 'collections' (/usr/lib/python3.10/collections/init.py)

this can be fixed by changing bottly.py in line 87 to
from collections.abc import MutableMapping as DictMixin

[medoc92]

The WebUI is still maintained with recoll on its repo web site (framagit): https://framagit.org/medoc92/recollwebui
The bottle version there fixes this error.
Also see this comment from koniu for confirmation: #83 (comment)