Ruby client: escape path parameters

Path parameters should be escaped when encoded into the path.

In the path '/pet/{petId}' let's pretend petId is a string instead of a
number.

If the user uses "Bobby" as the petId then they correctly get the path
'/pet/Bobby'.
But if they put 'Bobby/Tables' as the petId then they used to get the
path '/pet/Bobby/Tables' which will be interpreted by the server as a
different route.

Using CGI::Escape they now get '/pet/Bobby%2FTables' which is correct.

modules/openapi-generator/src/main/resources/ruby-client/api.mustache

@@ -3,6 +3,7 @@
 =end
 
 require 'uri'
+require 'cgi'
 
 module {{moduleName}}
 {{#operations}}
@@ -123,7 +124,7 @@ module {{moduleName}}
       {{/hasValidation}}
       {{/allParams}}
       # resource path
-      local_var_path = '{{{path}}}'{{#pathParams}}.sub('{' + '{{baseName}}' + '}', {{paramName}}.to_s){{/pathParams}}
+      local_var_path = '{{{path}}}'{{#pathParams}}.sub('{' + '{{baseName}}' + '}', CGI.escape({{paramName}}.to_s)){{/pathParams}}
 
       # query parameters
       query_params = opts[:query_params] || {}