Update photo manager version to 0.5.1-dev.2.

pubspec.lock

     dependency: transitive
     description:
       name: archive
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.11"
   args:
     dependency: transitive
     description:
       name: args
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.2"
   async:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.4.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.5"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.2"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.14.11"
   convert:
     dependency: transitive
     description:
       name: convert
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.1"
   crypto:
     dependency: transitive
     description:
       name: crypto
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.3"
   flutter:
     dependency: transitive
     description:
       name: image
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.4"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "0.12.6"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.8"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.6.4"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.0+1"
   petitparser:
     dependency: transitive
     description:
       name: petitparser
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.4.0"
   photo_manager:
     dependency: "direct main"
     description:
       name: photo_manager
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.0"
+    version: "0.5.1-dev.2"
   quiver:
     dependency: transitive
     description:
       name: quiver
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.5"
   sky_engine:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.5"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.9.3"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.5"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.11"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.6"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.8"
   xml:
     dependency: transitive
     description:
       name: xml
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "3.5.0"
 sdks:

pubspec.yaml

   flutter:
     sdk: flutter
 
-  photo_manager: ^0.5.0
+  photo_manager: ^0.5.1-dev.2
   # photo_manager:
   #   git:
   #     url: https://github.com/CaiJingLong/flutter_photo_manager.git