Pin setuptools<82 in requirements.txt to prevent upgrade by deps

The CI setuptools pin was being overridden by --upgrade when
installing requirements. Pin it in requirements.txt itself to
prevent cityloc breakage from pkg_resources removal.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: vthorsteinsson

requirements.txt

@@ -10,6 +10,8 @@ sqlalchemy2-stubs>=0.0.2a38
 sqlalchemy-stubs>=0.4
 # Server
 gevent>=24.2.1
+# Pin setuptools<82: version 82 removed pkg_resources, breaking cityloc
+setuptools>=67,<82
 # Util
 cachetools>=5.5.2
 requests>=2.32.3