Similar to ruff.yaml, it's simpler to run the codespell command directly
from a workflow file. And developers can run codespell directly from the
command line without the need for options, or just use pre-commit.
This commit also applies a specific version to codespell, same as
pre-commit (introduced in a166d805f4).
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>