Extension manager failing on urllib3 dependency (Mac, Inkscape 1.1)
#### Summary:
On macOS, the Extension Manager does not function in Inkscape 1.1 (c4e8f9e, 2021-05-24).
#### Steps to reproduce:
* Open Inkscape 1.1 (Mac)
* Select from the menu **Extensions>Manage Extensions**
#### What happened?
A Traceback:
```
Traceback (most recent call last):
File "extension-manager-bootstrap.py", line 133, in <module>
Bootstrap().run()
File "/Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/inkex/base.py", line 131, in run
self.save_raw(self.effect())
File "extension-manager-bootstrap.py", line 78, in effect
if self.install_fallback():
File "extension-manager-bootstrap.py", line 96, in install_fallback
from urllib3.exceptions import NewConnectionError
ModuleNotFoundError: No module named 'urllib3'
```
This appears to be a Mac-specific packaging error. Other extensions do appear to be working in general.
#### What should have happened?
The Extension manager should open. (Or, it should be removed from the menu.)
#### Version Info:
Inkscape 1.1 (c4e8f9e, 2021-05-24)
macOS 10.14
issue