ci_scripts: check_versions.py: fix docs path

We were still using the old docs/source/packages path, rather than
the docs/packages path in python-wheels.

AI-Generated: Uses Claude Sonnet 5

Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>

Author: threexc

ci_scripts/check_versions.py

@@ -166,7 +166,7 @@ def create_deprecation_pr(package: str, reason: str) -> Optional[str]:
         git_run("fetch", "origin")
         git_run("switch", "main")
 
-        yaml_file = Path(f"docs/source/packages/{package}.yaml")
+        yaml_file = Path(f"docs/packages/{package}.yaml")
         if not yaml_file.exists():
             print(f"    [!] YAML file for {package} does not exist")
             return None