fix sdk constraint

peng8350 · web-flow · commit f56715c26adb · 2021-03-18T23:34:30.000+08:00
diff --git a/pubspec.yaml b/pubspec.yaml
@@ -1,11 +1,11 @@
 name: pull_to_refresh
 description: a widget provided to the flutter scroll component drop-down refresh and pull up load.
-version: 1.6.4
+version: 1.6.4-nullsafety.0
 homepage: https://github.com/peng8350/flutter_pulltorefresh
 
 environment:
   sdk: '>=2.12.0 <3.0.0'
-  flutter: ">=0.1.4 <2.0.0"
+  flutter: ">=2.0.0"
 
 dependencies:
   flutter:
