[API] Adds .deprecation to x-pack template prefixes

Author: picandocodigo

api-spec-testing/test_file.rb

@@ -305,7 +305,7 @@ def clear_templates_xpack(client)
         end
 
         def xpack_template?(template)
-          xpack_prefixes = ['.monitoring', '.watch', '.triggered-watches', '.data-frame', '.ml-', '.transform', 'data-streams-mappings'].freeze
+          xpack_prefixes = ['.monitoring', '.watch', '.triggered-watches', '.data-frame', '.ml-', '.transform', 'data-streams-mappings', '.deprecation-'].freeze
           xpack_prefixes.map { |a| return true if a.include? template }
 
           XPACK_TEMPLATES.include? template