Downgrade flutter sdk versions. (#1305)

dart-api-examples/add-punctuations/pubspec.yaml

@@ -6,7 +6,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23

dart-api-examples/audio-tagging/pubspec.yaml

@@ -6,7 +6,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23

dart-api-examples/keyword-spotter/pubspec.yaml

@@ -6,7 +6,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23

dart-api-examples/non-streaming-asr/pubspec.yaml

@@ -6,7 +6,7 @@ version: 1.0.0
 # repository: https://github.com/my_org/my_repo
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 # Add regular dependencies here.
 dependencies:

dart-api-examples/speaker-identification/pubspec.yaml

@@ -6,7 +6,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23

dart-api-examples/streaming-asr/pubspec.yaml

@@ -7,7 +7,7 @@ version: 1.0.0
 # repository: https://github.com/my_org/my_repo
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 # Add regular dependencies here.
 dependencies:

dart-api-examples/tts/pubspec.yaml

@@ -4,7 +4,7 @@ version: 1.0.0
 # repository: https://github.com/my_org/my_repo
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 # Add regular dependencies here.
 dependencies:

dart-api-examples/vad-with-non-streaming-asr/pubspec.yaml

@@ -7,7 +7,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23

dart-api-examples/vad/pubspec.yaml

@@ -6,7 +6,7 @@ description: >
 version: 1.0.0
 
 environment:
-  sdk: ^3.4.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   sherpa_onnx: ^1.10.23