Due to the fact that not all PSK credentials consist of UTF-8 strings, the API in dart_tinydtls to accept Uint8Lists as parameters instead of Strings.
This PR updates the CoAP API accordingly, while also upgrading dart_tinydtls to the latest version, which also fixes some issues with connections that are closed by a peer due to an error.
Due to the fact that not all PSK credentials consist of UTF-8 strings, the API in dart_tinydtls to accept
Uint8Lists as parameters instead ofStrings.This PR updates the CoAP API accordingly, while also upgrading dart_tinydtls to the latest version, which also fixes some issues with connections that are closed by a peer due to an error.