bug(understanding deis): missed one

Author: slack

mkdocs.yml

@@ -6,7 +6,7 @@ site_name: Deis Documentation
 pages:
   - Welcome: index.md
   - Quick Start: installing-workflow/quickstart.md
-  - Understanding Deis:
+  - Understanding Workflow:
     - Concepts: understanding-workflow/concepts.md
     - Architecture: understanding-workflow/architecture.md
     - Components: understanding-workflow/components.md