Add speaker identification and verification exmaple for Dart API (#1194)

scripts/dart/speaker-id-pubspec.yaml

@@ -0,0 +1,18 @@
+name: speaker_identification
+
+description: >
+  This example demonstrates how to use the Dart API for speaker identification.
+
+version: 1.0.0
+
+environment:
+  sdk: ^3.4.0
+
+dependencies:
+  sherpa_onnx:
+    path: ../../flutter/sherpa_onnx
+  path: ^1.9.0
+  args: ^2.5.0
+
+dev_dependencies:
+  lints: ^3.0.0