Bump to v0.18.1, to include elastix-2023-09-18

Author: N-Dekker

setup.py

@@ -18,7 +18,7 @@
 
 setup(
     name=package_name,
-    version='0.18.0',
+    version='0.18.1',
     author='Insight Software Consortium',
     author_email='itk+community@discourse.itk.org',
     packages=['itk'],