automate running of process_mapping.py

[soxofaan]

process_mapping.py is a tool to generate the openEO process mapping documentation page https://open-eo.github.io/openeo-python-client/process_mapping.html

but it currently depends on running it manually:

openeo-python-client/docs/process_mapping.py

Line 16 in 4857ed7

# TODO: automate running of this tool. E.g. use https://nedbatchelder.com/code/cog

last run at the moment was from august 2023 howeverr

openeo-python-client/docs/process_mapping.rst

Line 332 in 4857ed7

:subscript:`(Table autogenerated on 2023-08-07)`

[soxofaan]

at minimum this could just be a test that fails when things are out of sync (e.g. run tool and check git diff)