update variable name (#36548)

Co-authored-by: Catalina Peralta <caperal@microsoft.com>

tools/azure-sdk-tools/pypi_tools/pypi.py

@@ -68,5 +68,5 @@ class PyPIClient:
         If there are different, it means the latest is not a stable
         """
         versions = self.get_ordered_versions(package_name)
-        pre_releases = [version for version in versions if not version.is_prerelease]
-        return (versions[-1], pre_releases[-1])
+        stable_releases = [version for version in versions if not version.is_prerelease]
+        return (versions[-1], stable_releases[-1])