This change adds support for the 'include_type_name' parameter for the
indices.get API. This parameter, which defaults to `false` starting in 7.0,
changes the response to not include the indices type names any longer.
If the parameter is set in the request, we additionally emit a deprecation
warning since using the parameter should be only temporarily necessary while
adapting to the new response format and we will remove it with the next major
version.
