Test on oldest supported Dart SDK

pkgs/stream_channel/.travis.yml

diff --git a/pkgs/stream_channel/.travis.yml b/pkgs/stream_channel/.travis.yml
index 45359fb..69f24c3 100644
--- a/pkgs/stream_channel/.travis.yml
+++ b/pkgs/stream_channel/.travis.yml
@@ -1,12 +1,23 @@
 language: dart
 
 dart:
-  - dev
+- 2.0.0
+- dev
+
 dart_task:
-  - test: --platform vm
-  - test: --platform firefox -j 1
-  - dartfmt
-  - dartanalyzer
+- test: --platform vm,chrome
+
+matrix:
+  include:
+  # Only validate formatting using the dev release
+  - dart: dev
+    dart_task: dartfmt
+  - dart: dev
+    dart_task:
+      dartanalyzer: --fatal-infos --fatal-warnings .
+  - dart: 2.0.0
+    dart_task:
+      dartanalyzer: --fatal-warnings .
 
 # Only building master means that we don't run two builds for each pull request.
 branches:
@@ -14,4 +25,4 @@
 
 cache:
   directories:
-    - $HOME/.pub-cache
+  - $HOME/.pub-cache