bugfix: Request Signing: This change allows requests to a service to be signed if the api.json doesn't specify a signatureVersion or authtype, but the configuration has a signatureVersion specified. Prior to this change, the logic to create a signer would use signatureVersion specified in the config, but the code would never reach it if api.json signatureVersion or authtype weren't defined.
feature: Personalize: AWS Personalize: Adds ability to create a solution version using FULL or UPDATE training mode
feature: Retry: retry all 429 status code exceptions