add overlays examples (#991)

cmd/kusk/internal/overlays/overlay.yaml

@@ -7,6 +7,6 @@ actions:
     remove: true
   - target: "$.info"
     update:
-      title: Overlayed!
+      title: Overlayed
       description: |
         This API has been overlayed 😎

examples/overlays/openapi.yaml

@@ -0,0 +1,22 @@
+openapi: 3.0.0
+servers:
+  - url: http://api.mydomain.com
+info:
+  title: simple-api
+  version: 0.1.0
+paths:
+  /hello:
+    get:
+      summary: Returns a Hello world to the user
+      responses:
+        '200':
+          description: A simple hello world!
+          content:
+            application/json; charset=utf-8:
+              schema:
+                type: object
+                properties:
+                  message:
+                    type: string
+                required:
+                  - message

examples/overlays/overlay.yaml

@@ -0,0 +1,8 @@
+overlays: 1.0.0
+extends: ./openapi.yaml
+actions:
+  - target: "$"
+    update:
+      x-kusk: 
+        mocking:
+          enabled: true