Upgrading CRT version
- API CHANGE: awscrt.auth.AwsSigningConfig.signed_body_value is now a string instead of an enum.
- API CHANGE: Added check for iOS platform
- BUGFIX: Fixes possible crash If the underlying http_message get destroyed before the destructor of HttpMessage.
- BUGFIX: Fixes a crash when shutting down an mqtt connection with an incomplete request with no callback from aws-c-mqtt
- BUGFIX: Crash fix caused by passing null into a shared_ptr reset