test on oldest supported SDK (#48)

* update min sdk
* Fix references to dartlang.org
diff --git a/.travis.yml b/.travis.yml
index 7dee3cc..3537f65 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,9 +2,11 @@
 
 dart:
   - dev
+  - 2.2.0
+
 dart_task:
   - test
-  - dartanalyzer
+  - dartanalyzer: --fatal-infos --fatal-warnings .
 
 matrix:
   include:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fca454b..c95f7f1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 * Fixed issue where throwing `RpcException.methodNotFound` in an asynchronous
   fallback handler would not result in the next fallback being executed.
+* Updated minimum SDK to Dart `2.2.0`.
 
 ## 2.1.0
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 89fb7b8..0f55fb7 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -5,7 +5,7 @@
 homepage: https://github.com/dart-lang/json_rpc_2
 
 environment:
-  sdk: ">=2.0.0 <3.0.0"
+  sdk: ">=2.2.0 <3.0.0"
 
 dependencies:
   stack_trace: ^1.0.0
diff --git a/test/server/parameters_test.dart b/test/server/parameters_test.dart
index 8b8d07f..069daf3 100644
--- a/test/server/parameters_test.dart
+++ b/test/server/parameters_test.dart
@@ -18,7 +18,7 @@
         'string': 'zap',
         'list': [1, 2, 3],
         'date-time': '1990-01-01 00:00:00.000',
-        'uri': 'http://dartlang.org',
+        'uri': 'https://dart.dev',
         'invalid-uri': 'http://[::1',
         'map': {'num': 4.2, 'bool': false}
       });
@@ -34,7 +34,7 @@
             'string': 'zap',
             'list': [1, 2, 3],
             'date-time': '1990-01-01 00:00:00.000',
-            'uri': 'http://dartlang.org',
+            'uri': 'https://dart.dev',
             'invalid-uri': 'http://[::1',
             'map': {'num': 4.2, 'bool': false}
           }));
@@ -241,12 +241,12 @@
     });
 
     test('[].asUri returns URI parameters', () {
-      expect(parameters['uri'].asUri, equals(Uri.parse('http://dartlang.org')));
+      expect(parameters['uri'].asUri, equals(Uri.parse('https://dart.dev')));
     });
 
     test('[].asUriOr returns URI parameters', () {
       expect(parameters['uri'].asUriOr(Uri.parse('http://google.com')),
-          equals(Uri.parse('http://dartlang.org')));
+          equals(Uri.parse('https://dart.dev')));
     });
 
     test('[].asUri fails for non-URI parameters', () {