Rebuild 4: retire support for Pythons 3.6, 3.7 and 3.8, and add support for Python 3.13 via pin webob >=1.8.9

[valeriupredoi]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• [ ] Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Pythons:

• 3.6
• 3.7
• 3.8
  -> retired support

Added support for Python 3.13 via upstream ESGF/esgf-pyclient#109

[valeriupredoi]

@conda-forge-admin, please rerender

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.
I do have some suggestions for making it better though...

For recipe/meta.yaml:

• No valid build backend found for Python recipe for package esgf-pyclient using pip. Python recipes using pip need to explicitly specify a build backend in the host section. If your recipe has built with only pip in the host section in the past, you likely should add setuptools to the host section of your recipe.

[valeriupredoi]

@conda-forge-admin, please rerender

[valeriupredoi]

@conda-forge-admin, please rerender

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-webservice.

I tried to rerender for you, but it looks like there was nothing to do.

_{This message was generated by GitHub actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/11555700371.}

[valeriupredoi]

aw man, I thought I was going bananas - Azure builds are failing across the board (ie not triggering) https://conda-forge.org/status/

[valeriupredoi]

PLEASE DO NOT MERGE just yet, Azure's bellyup, we need the actual build test to run before doing anything

[valeriupredoi]

OK third time lucky - @conda-forge-admin please restart ci

[valeriupredoi]

the feedstock is still sick, the error the build fails with needs looking at by @conda-forge-admin https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=1067569&view=logs&j=7b6f2c87-f3a7-5133-8d84-7c03a75d9dfc&t=e8470a31-8fae-5a2d-4ba5-ddfbee14fe43

[valeriupredoi]

I am going to close this and open a new PR - fresh air may help with this

[valeriupredoi]

rebuilt and redeployed via #28