404 error for Scotch tarball

[joewallwork]

The latest Docker build failed due to the Scotch tarball giving a 404 error:
https://github.com/mesh-adaptation/docs/actions/runs/22567204662/job/65365886897

i.e., the following doesn't work
https://web.cels.anl.gov/projects/petsc/download/externalpackages/scotch-v7.0.11.tar.gz

[joewallwork]

While the page still gives a 404, it looks like this was an intermittent issue with PETSc. CI passed after being re-triggered in #175.