Pin args to 0.13.7 to avoid version conflict (#12208)

dev/automated_tests/pubspec.yaml

 name: flutter_automated_tests
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   flutter_test:

dev/benchmarks/complex_layout/pubspec.yaml

@@ -2,6 +2,7 @@ name: complex_layout
 description: A benchmark of a relatively complex layout.
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   flutter_driver:

dev/integration_tests/flavors/pubspec.yaml

@@ -2,6 +2,7 @@ name: flavors
 description: Integration test for build flavors.
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   flutter_driver:

dev/integration_tests/platform_interaction/pubspec.yaml

@@ -2,6 +2,7 @@ name: platform_interaction
 description: Integration test for platform interactions.
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   flutter_driver:

dev/integration_tests/ui/pubspec.yaml

@@ -2,6 +2,7 @@ name: integration_ui
 description: Flutter non-plugin UI integration tests.
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   flutter_driver:

examples/catalog/pubspec.yaml

 name: sample_catalog
 description: A collection of Flutter sample apps
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
   path: ^1.4.0

examples/flutter_gallery/pubspec.yaml

 name: flutter_gallery
 dependencies:
+  args: ^0.13.7
   collection: '>=1.9.1 <2.0.0'
   intl: '>=0.14.0 <0.16.0'
   string_scanner: ^1.0.0

examples/hello_world/pubspec.yaml

 name: hello_world
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
 

examples/platform_channel/pubspec.yaml

 name: platform_channel
 
 dependencies:
+  args: ^0.13.7
   flutter:
     sdk: flutter
 

packages/flutter/pubspec.yaml

@@ -5,6 +5,7 @@ description: A framework for writing Flutter applications
 homepage: http://flutter.io
 
 dependencies:
+  args: ^0.13.7
   collection: '>=1.9.1 <2.0.0'
   http: '>=0.11.3+12'
   intl: '>=0.14.0 <0.16.0'

packages/flutter_test/pubspec.yaml

 name: flutter_test
 version: 0.0.14-dev
 dependencies:
+  args: ^0.13.7
   # The flutter tools depend on very specific internal implementation
   # details of the 'test' package, which change between versions, so
   # here we pin it precisely to avoid version skew across our