[ci,codespell] Ignore all false positives

Plus, ignore everything in pybind11.  Since this is code we import
from outside I couldn't be bothered to fix the typos there, too.

.gitlab-ci.yml

@@ -65,3 +65,5 @@ code-spelling-check:
   image: registry.dune-project.org/docker/ci/debian:11
   script:
   - codespell
+    --ignore-words-list te,inout,incrementall,iif,\trun,referr,ba
+    --skip pybind11