Copier could not load some Jinja extensions

copier copy --trust --vcs-ref 2.10.0 https://gitlab.developers.cam.ac.uk/uis/devops/webapp-boilerplate.git ./my-example-webapp

throws error

Copier could not load some Jinja extensions:
No module named 'copier_templates_extensions'
Make sure to install these extensions alongside Copier itself.
See the docs at https://copier.readthedocs.io/en/latest/configuring/#jinja_extensions

for tags 2.10.0 and above. README.md needs updating or an alternate approach.