Correct wolfssl-examples script fetch branch

[gojimmypi]

Updates workflow with the proper curl fetch URL for example code.

Related to #20

• Note on workflow warning:

--no-wolfssl_client_dtls: there's no wolfssl_client_dtls example for the v5.8.2 release
⚠ WARN: Unknown example in flag "--no-wolfssl_client_dtls" under FQBN "arduino:avr:nano" (ignored)
--no-wolfssl_server_dtls: there's no wolfssl_server_dtls example for the v5.8.2 release
⚠ WARN: Unknown example in flag "--no-wolfssl_server_dtls" under FQBN "arduino:avr:nano" (ignored)

The new TLS examples are not present here (yet), and were not included in the most recent Arduino release 5.8.2

See:

• https://github.com/wolfSSL/Arduino-wolfSSL/tree/main/examples
• https://github.com/wolfSSL/wolfssl-examples/tree/master/Arduino/sketches