migrate to `dart analyze`

(warnings are now fatal by default)

pkgs/package_config/.travis.yml

diff --git a/pkgs/package_config/.travis.yml b/pkgs/package_config/.travis.yml
index 3a47bb5..c4e5bdb 100644
--- a/pkgs/package_config/.travis.yml
+++ b/pkgs/package_config/.travis.yml
@@ -5,7 +5,7 @@
 dart_task:
   - test
   - dartfmt
-  - dartanalyzer: --fatal-warnings --fatal-infos .
+  - dart analyze --fatal-infos .
 
 matrix:
   include: