- pubspec.yaml flutter constraint fixed

Author: luis901101

example/pubspec.lock

@@ -165,4 +165,4 @@ packages:
     version: "2.0.0+11"
 sdks:
   dart: ">=2.12.0 <3.0.0"
-  flutter: ">=1.12.13"
+  flutter: ">=1.20.0"

pubspec.lock

@@ -48,3 +48,4 @@ packages:
     version: "2.1.0"
 sdks:
   dart: ">=2.12.0 <3.0.0"
+  flutter: ">=1.20.0"

pubspec.yaml

@@ -5,6 +5,7 @@ homepage: https://github.com/luis901101/zsdk
 
 environment:
   sdk: '>=2.12.0 <3.0.0'
+  flutter: '>=1.20.0'
 
 dependencies:
   flutter:
@@ -31,7 +32,7 @@ flutter:
   # For details regarding assets in packages, see
   # https://flutter.io/assets-and-images/#from-packages
   #
-  # An image asset can refer to one or more resolution-specific "variants", see
+  # An image asset can refer to one or more resolution-specific 'variants", see
   # https://flutter.io/assets-and-images/#resolution-aware.
 
   # To add custom fonts to your plugin package, add a fonts section here,