nextcloud: Add web support

packages/nextcloud/lib/nextcloud.dart

@@ -1,12 +1,12 @@
 library nextcloud;
 
 import 'dart:convert';
-import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:crypto/crypto.dart';
 import 'package:nextcloud/nextcloud.dart';
 import 'package:nextcloud/src/nextcloud.openapi.dart' as openapi;
+import 'package:universal_io/io.dart';
 import 'package:version/version.dart';
 import 'package:xml/xml.dart' as xml;
 

packages/nextcloud/lib/src/nextcloud.openapi.dart

@@ -2,11 +2,11 @@
 // ignore_for_file: camel_case_types
 // ignore_for_file: public_member_api_docs
 import 'dart:convert';
-import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:cookie_jar/cookie_jar.dart';
 import 'package:json_annotation/json_annotation.dart';
+import 'package:universal_io/io.dart';
 
 export 'package:cookie_jar/cookie_jar.dart';
 

packages/nextcloud/pubspec.yaml

@@ -10,6 +10,7 @@ dependencies:
   crypton: ^2.0.5
   intl: ^0.18.0
   json_annotation: ^4.7.0
+  universal_io: ^2.2.0
   version: ^3.0.2
   xml: ^6.1.0
   xml_annotation: ^2.2.0