Fixes misplaced `*` in flag migration e.g. (#2197)

The embedded `personModelv1` in the `personModelv2` struct should not be
a pointer. The instantiation code later on already uses
`personModelv1{}` instead of `&personModelv1{}` and does not need
updating, just the initial struct definition.

CONTRIBUTING.md

@@ -105,7 +105,7 @@ struct personModelv1 {
 
 // Added!
 struct personModelv2 {
-  *personModelv1
+  personModelv1
   IsWizard bool
 }