Update polymer expressions version to match dart-archive/polymer-expressions#10

Author: tvolkert

pubspec.yaml

@@ -16,7 +16,7 @@ dependencies:
   initialize: '>=0.5.1+3 <0.7.0'
   logging: '>=0.9.2 <0.12.0'
   path: '>=0.9.0 <2.0.0'
-  polymer_expressions: '>=0.13.0+3 <0.14.0'
+  polymer_expressions: '>=0.13.1+1 <0.14.0'
   polymer_interop: '>=0.1.0+2 <0.2.0'
   smoke: '>=0.2.0 <0.4.0'
   source_maps: '>=0.9.4 <0.11.0'