update lock file

example/pubspec.lock

@@ -1,5 +1,5 @@
 # Generated by pub
-# See https://dart.dev/tools/pub/glossary#lockfile
+# See https://www.dartlang.org/tools/pub/glossary#lockfile
 packages:
   analyzer:
     dependency: transitive
@@ -21,7 +21,7 @@ packages:
       name: async
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.2.0"
+    version: "2.1.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -169,7 +169,7 @@ packages:
       name: pedantic
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.5.0"
   petitparser:
     dependency: transitive
     description:
@@ -204,7 +204,7 @@ packages:
       name: quiver
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.3"
+    version: "2.0.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -251,7 +251,7 @@ packages:
       name: test_api
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.2.5"
+    version: "0.2.4"
   typed_data:
     dependency: transitive
     description:
@@ -281,5 +281,5 @@ packages:
     source: hosted
     version: "2.1.15"
 sdks:
-  dart: ">=2.2.2 <3.0.0"
+  dart: ">=2.2.0 <3.0.0"
   flutter: ">=0.3.0 <2.0.0"