[Ruby][Faraday] Various improvements (#3520)

* update ruby faraday oas v2 samples

* skip some default tests in faraday

* add ruby faraday oas v3 client

* add tests, fix url

* add tests to CI

* fix file upload

* undo changes to ruby-client-petstore.sh

* test faraday first

* combine gemspec tempaltes

* test ruby faraday in drone.io

* use smaller image

* update bundler

* use official ruby image

* skip bundler installation

* skip autotest

* install make

* use different image

* skip ruby tests in drone.io

samples/client/petstore/ruby-faraday/docs/FormatTest.md

@@ -1,6 +1,7 @@
 # Petstore::FormatTest
 
 ## Properties
+
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **integer** | **Integer** |  | [optional] 
@@ -17,4 +18,24 @@ Name | Type | Description | Notes
 **uuid** | **String** |  | [optional] 
 **password** | **String** |  | 
 
+## Code Sample
+
+```ruby
+require 'Petstore'
+
+instance = Petstore::FormatTest.new(integer: null,
+                                 int32: null,
+                                 int64: null,
+                                 number: null,
+                                 float: null,
+                                 double: null,
+                                 string: null,
+                                 byte: null,
+                                 binary: null,
+                                 date: null,
+                                 date_time: null,
+                                 uuid: 72f98069-206d-4f12-9f12-3d1e525a8e84,
+                                 password: null)
+```
+