refactor: upgrade to Dart 2.16 and Flutter 2.10 (#8)

src/my_plugin/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.14.0 <3.0.0"
-  flutter: ">=2.5.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin:

src/my_plugin_android/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.14.0 <3.0.0"
-  flutter: ">=2.5.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin:

src/my_plugin_ios/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.14.0 <3.0.0"
-  flutter: ">=2.5.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin:

src/my_plugin_linux/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin:

src/my_plugin_macos/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin:

src/my_plugin_platform_interface/pubspec.yaml

@@ -3,8 +3,8 @@ description: A common platform interface for the my_plugin plugin.
 version: 0.1.0+1
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 dependencies:
   flutter:

src/my_plugin_windows/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.0+1
 publish_to: none
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.16.0 <3.0.0"
+  flutter: ">=2.10.0"
 
 flutter:
   plugin: