Support string_scanner 1.0.0.

R=kevmoo@google.com, cbracken@google.com

Review URL: https://codereview.chromium.org//2085783002 .

pkgs/yaml/CHANGELOG.md

diff --git a/pkgs/yaml/CHANGELOG.md b/pkgs/yaml/CHANGELOG.md
index e1a43b2..da7f6bd 100644
--- a/pkgs/yaml/CHANGELOG.md
+++ b/pkgs/yaml/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 2.1.10
+
+* Support `string_scanner` 1.0.0.
+
 ## 2.1.9
 
 * Fix all strong-mode warnings.

pkgs/yaml/pubspec.yaml

diff --git a/pkgs/yaml/pubspec.yaml b/pkgs/yaml/pubspec.yaml
index 87ddd5b..990054f 100644
--- a/pkgs/yaml/pubspec.yaml
+++ b/pkgs/yaml/pubspec.yaml
@@ -1,12 +1,12 @@
 name: yaml
-version: 2.1.9
+version: 2.1.10
 author: "Dart Team <misc@dartlang.org>"
 homepage: https://github.com/dart-lang/yaml
 description: A parser for YAML.
 dependencies:
   charcode: "^1.1.0"
   collection: ">=1.1.0 <2.0.0"
-  string_scanner: "^0.1.4"
+  string_scanner: ">=0.1.4 <2.0.0"
   source_span: ">=1.0.0 <2.0.0"
 dev_dependencies:
   path: ">=1.2.0 <2.0.0"