docs action failed after latest modernisation of poetry setup

[matentzn]

https://github.com/mapping-commons/sssom-py/actions/runs/16588754405/job/46919227485

cc @cthoyt (no need for you to step in, just FYI)

[matentzn]

@cthoyt maybe I would appreciate your advice :P No need to fix, just point a finger. I tried #602 but that did not work..

[cthoyt]

i'll take a look! this will be another good step away from poetry ;)