Better OpenAPI spec v3 support: allOf, anyOf, oneOf (#1360)

* add oneOf support to Ruby

* add anyOf support to ruby client

* add discriminator support to ruby client

* fix typo

* update samples, fix NPE

* better format in ruby generator

* fix test cases, disable mapping test

* fix update script, update samples

* add test, fix mapping

* update exit code

* reenabled discriminator test

* remove duplicated properties

* add test for duplicated properties

* update samples, add new spec

* fix ruby test cases

* fix hasMore after removing duplicates

* refactor method, comment out haskell client test

* fix hasMore and update samples

* fix parent detection

* fix discriminator check

* [haskell-http-client] need to use {{vars}}{{required}} instead of {{requiredVars}}

* remove deprecated methods in default codegen (#1031)

* regenerate samples

* remove commented code

samples/client/petstore/ruby/docs/Dog.md

@@ -3,8 +3,8 @@
 ## Properties
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**breed** | **String** |  | [optional] 
 **class_name** | **String** |  | 
 **color** | **String** |  | [optional] [default to 'red']
-**breed** | **String** |  | [optional]