Pass URI instead of String in README (#535)

Fixes #533

Use Uri.Parse to match the implementation

Author: eripe970

CHANGELOG.md

@@ -1,3 +1,5 @@
+## 0.13.1-dev
+
 ## 0.13.0
 
 * Stable null safety release.

README.md

@@ -15,7 +15,7 @@ you to make individual HTTP requests with minimal hassle:
 ```dart
 import 'package:http/http.dart' as http;
 
-var url = 'https://example.com/whatsit/create';
+var url = Uri.parse('https://example.com/whatsit/create');
 var response = await http.post(url, body: {'name': 'doodle', 'color': 'blue'});
 print('Response status: ${response.statusCode}');
 print('Response body: ${response.body}');
@@ -30,7 +30,7 @@ If you do this, make sure to close the client when you're done:
 ```dart
 var client = http.Client();
 try {
-  var uriResponse = await client.post('https://example.com/whatsit/create',
+  var uriResponse = await client.post(Uri.parse('https://example.com/whatsit/create'),
       body: {'name': 'doodle', 'color': 'blue'});
   print(await client.get(uriResponse.bodyFields['uri']));
 } finally {

pubspec.yaml

@@ -1,5 +1,5 @@
 name: http
-version: 0.13.0
+version: 0.13.1-dev
 homepage: https://github.com/dart-lang/http
 description: A composable, multi-platform, Future-based API for HTTP requests.