Remove -dev.infinity in SDK upper constraint

No longer require

Author: kevmoo

pubspec.yaml

@@ -5,7 +5,7 @@ author: Dart Team <[email protected]>
 homepage: https://github.com/dart-lang/convert
 
 environment:
-  sdk: '>=1.17.0 <2.0.0-dev.infinity'
+  sdk: '>=1.17.0 <2.0.0'
 
 dependencies:
   charcode: '^1.1.0'