Update proposals/propertyDependencies.md

Co-authored-by: Greg Dennis <[email protected]>

Author: jdesrosiers

proposals/propertyDependencies.md

@@ -36,6 +36,7 @@ specification](../jsonschema-core.html) also apply to this document.
 ## Overview
 
 ### Problem Statement
+
 A common need in JSON Schema is to select between one schema or another to
 validate an instance based on the value of some property in the JSON instance.
 There are a several patterns people use to accomplish this, but they all have