Fixed header values

Author: eldadfux

lib/client.js

@@ -9,7 +9,7 @@ class Client {
         this.endpoint = 'https://appwrite.io/v1';
         this.headers = {
             'content-type': '',
-            'x-sdk-version': 'appwrite:nodejs:2.2.0',
+            'x-sdk-version': 'appwrite:nodejs:2.2.1',
             'X-Appwrite-Response-Format' : '0.8.0',
         };
         this.selfSigned = false;
@@ -99,7 +99,7 @@ class Client {
      * @param value string
      */
     addHeader(key, value) {
-        this.headers[key.toLowerCase()] = value.toLowerCase();
+        this.headers[key.toLowerCase()] = value;
 
         return this;
     }

package.json

@@ -2,7 +2,7 @@
   "name": "node-appwrite",
   "homepage": "https://appwrite.io/support",
   "description": "Appwrite is an open-source self-hosted backend server that abstract and simplify complex and repetitive development tasks behind a very simple REST API",
-  "version": "2.2.0",
+  "version": "2.2.1",
   "license": "BSD-3-Clause",
   "main": "index.js",
   "repository": {