Add missing =

Author: thibaudcolas

tox.ini

@@ -18,7 +18,7 @@ basepython =
     py313: python3.13
 
 deps =
-    setuptools=75.8.0
+    setuptools==75.8.0
     pytest
     # Keep this in sync with the dependencies in setup.py, requirements.txt, tox.ini.
     lower_bound_deps: beautifulsoup4==4.4.1