Reword examples parent README with disclaimer (#445)

### Motivation

As we approach 1.0, we want more examples of how to use this package and
integrate with other packages in the ecosystem. However, these are
deliberately meant to be illustrative, and are often deliberately not
fully-featured. The README currently suggests using these as starter
projects, which implies something stronger.

### Modifications

Reword examples parent README with disclaimer
 
### Result

Docs clearer.

### Test Plan

None.

Author: simonjbeaumont

Examples/README.md

@@ -1,6 +1,10 @@
 # Examples of using Swift OpenAPI Generator
 
-All the examples are self-contained, so you can copy the package directory of your chosen example and use it as a starter template for your project.
+This directory contains examples of how to use Swift OpenAPI Generator and
+integrate with other packages in the ecosystem.
+
+> **Disclaimer:** Many of these examples have been deliberately simplified and are
+> intended for illustrative purposes only.
 
 ## Getting started