Add opta compile example workflow

Author: pennam

.github/workflows/compile-examples.yml

@@ -64,6 +64,8 @@ jobs:
             platform-name: arduino:mbed_nano
           - fqbn: arduino:mbed_nicla:nicla_vision
             platform-name: arduino:mbed_nicla
+          - fqbn: arduino:mbed_opta:opta
+            platform-name: arduino:mbed_opta
 
         # Make board type-specific customizations to the matrix jobs
         include: