zodburi: v↑ to 3.0.0 for python3
A new version of zodburi has been released [1] that removes Python2 compatibility shims [2] and is therefore needed to successfully run 'wendelin.core' tests with python3 [3].
Suggested by @kirr.
[1] https://pypi.org/project/zodburi/3.0.0/ [2] https://github.com/Pylons/zodburi/commit/a00fea755 [3] https://lab.nexedi.com/nexedi/wendelin.core/-/merge_requests/35
Let's wait for tests to see if everything is ok.