steal Ruby's Master heading for pre-release changelog documentation

Author: CaseyFaist

CHANGELOG.md

@@ -1,18 +1,16 @@
 # Python Buildpack Changelog
 
-# 156 (2019-09)
+# Master
 
-## (2019-09-12)
-Bump Hatchet tests to point at new default python version.
+- Bump Hatchet tests to point at new default python version.
 
-## (2019-09-11)
-Python 3.6.9 and 3.7.4 now available.
+- Python 3.6.9 and 3.7.4 now available.
 
-## (2019-09-11)
-Move get-pip utility to S3
+- Move get-pip utility to S3
 
-## (2019-09-10)
-Build utility and documentation updates
+- Build utility and documentation updates
+
+--------------------------------------------------------------------------------
 
 # 155 (2019-08-22)