Notes for future upgrade of pgweb to bookworm

Afaik, moving support of pgweb from buster to bookworm isn't planned yet, but here's a note that may be useful when
thisis the case.
 

To avoid crashes during deployment, the following dependencies must be updated in requirements.txt:
bleach==3.1.4 -> bleach>=3.3.1
Babel==2.6.0 -> Babel>=2.7.0

Otherwise, there's an issue regarding collections in python3:
ImportError: cannot import name 'Mapping' from 'collections

I don't think it's useful to send a patch yet, but let me know if this is the case.
-- 
Célestin Matte