docs: Doc tweak

Author: Alan Christie

README.rst

@@ -16,7 +16,9 @@ Informatics Matters Data Manager Workflow Decoder
 A package that simplifies the validation and decoding of Data Manager
 Workflow definitions.
 
-## Installation (Python)
+Installation (Python)
+=====================
+
 The Job decoder is published on `PyPI`_ and can be installed from there:
 
     pip install im-data-manager-workflow-decoder