Update MigrationGuides.md

Author: stephencelis

Sources/ComposableArchitecture/Documentation.docc/Articles/MigrationGuides.md

@@ -14,6 +14,7 @@ APIs, and these guides contain tips to do so.
 
 ## Topics
 
+- <doc:MigratingTo1.14>
 - <doc:MigratingTo1.13>
 - <doc:MigratingTo1.12>
 - <doc:MigratingTo1.11>