Pin test version to 1.9.2 (#68)

Author: f3ath

pubspec.yaml

@@ -9,7 +9,7 @@ dependencies:
   http: ^0.12.0
   collection: ^1.14.11
 dev_dependencies:
-  test: ^1.6.1
+  test: 1.9.2
   json_matcher: ^0.2.3
   stream_channel: ^1.6.8
   uuid: ^2.0.1