Added support for version v2.1-21.2.00.00 of the DocuSign eSignature API.
Updated the SDK release version.
Removed return type from api as the mixed data-type is not fully supported in PHP 7.4. It is unable to handle null value which has been tackled in PHP 8. This change will be reverted in November 2021 when PHP will stop support for 7.4 as well.
Changed