Upgrade fonttools to 4.18.1

Test: make
Change-Id: I9193fa1e27c09057d2263373a6d80f39d8775fde
diff --git a/setup.py b/setup.py
index df01004..be33a73 100755
--- a/setup.py
+++ b/setup.py
@@ -441,7 +441,7 @@
 
 setup_params = dict(
 	name="fonttools",
-	version="4.18.0",
+	version="4.18.1",
 	description="Tools to manipulate font files",
 	author="Just van Rossum",
 	author_email="just@letterror.com",