Remove deprecated types-pkg-resources from dev-requirements

types-pkg-resources has been yanked from PyPI and merged into
types-setuptools (already in requirements). This was breaking the
code-quality CI check on the docs branch.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: joostboon

dev-requirements.txt

@@ -4,7 +4,6 @@ pre-commit
 mypy
 
 # MyPy stubs
-types-pkg-resources
 types-requests
 networkx-stubs
 types-python-dateutil