Fix travis config (#71)

diff --git a/.travis.yml b/.travis.yml
index c1d0163..416dd71 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,19 +9,16 @@
     fi
 
 dart:
+  - 2.2.0
   - dev
 
 dart_task:
-  - test: --platform vm
-  - dartanalyzer
-  - dartfmt
+  - test
 
-# 1.24 analyzer breaks on generic method syntax. Remove this exclusion when
-# there is a new stable version.
 matrix:
-  exclude:
-  - dart: stable
-    dart_task: dartanalyzer
+  include:
+  - dart: dev
+    dart_task: dartfmt
 
 # Only building master means that we don't run two builds for each pull request.
 branches:
diff --git a/analysis_options.yaml b/analysis_options.yaml
index d9715a7..a705446 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -1,5 +1,4 @@
 analyzer:
-  strong-mode: true
   errors:
     unused_import: error
     unused_local_variable: error
diff --git a/pubspec.yaml b/pubspec.yaml
index e34cd71..ce172f1 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,9 +2,11 @@
 author: "Dart Team <misc@dartlang.org>"
 homepage: https://github.com/dart-lang/http_io
 description: HTTP Client and Server APIs.
+
 environment:
-  sdk: ">=2.0.0-dev.17.0 <3.0.0"
+  sdk: ">=2.2.0 <3.0.0"
+
 dev_dependencies:
-  convert: "^2.0.1"
-  crypto: "^2.0.2+1"
+  convert: ^2.0.1
+  crypto: ^2.0.2+1
   test: ^1.0.0