CODECOV_TOKEN needs to be updated

[jsignell]

I noticed in the codecov report on #809 that it says: "Report is 127 commits behind main"

I think this has to do with an expired token defined here:

pystac-client/.github/workflows/continuous-integration.yml

Line 42 in 46e3fbc

token: ${{ secrets.CODECOV_TOKEN }}

You can see the error in the github actions CI workflow:
https://github.com/stac-utils/pystac-client/actions/runs/16374666177/job/46271469636#step:8:249