remove the flutter upper bound as requested by pub

Author: letsar

example/pubspec.lock

@@ -106,7 +106,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.1"
   stack_trace:
     dependency: transitive
     description:
@@ -141,7 +141,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19"
+    version: "0.3.0"
   typed_data:
     dependency: transitive
     description:
@@ -155,7 +155,7 @@ packages:
       name: value_layout_builder
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.0"
+    version: "0.3.0"
   vector_math:
     dependency: transitive
     description:
@@ -165,4 +165,4 @@ packages:
     version: "2.1.0"
 sdks:
   dart: ">=2.12.0 <3.0.0"
-  flutter: ">=1.24.0-10.2.pre <3.0.0"
+  flutter: ">=1.24.0-10.2.pre"

pubspec.lock

@@ -92,7 +92,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.1"
   stack_trace:
     dependency: transitive
     description:
@@ -127,7 +127,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19"
+    version: "0.3.0"
   typed_data:
     dependency: transitive
     description:
@@ -151,4 +151,4 @@ packages:
     version: "2.1.0"
 sdks:
   dart: ">=2.12.0 <3.0.0"
-  flutter: ">=1.24.0-10.2.pre <3.0.0"
+  flutter: ">=1.24.0-10.2.pre"

pubspec.yaml

@@ -5,7 +5,7 @@ homepage: https://github.com/letsar/overflow_view
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=1.24.0-10.2.pre <3.0.0"
+  flutter: ">=1.24.0-10.2.pre"
 
 dependencies:
   flutter: