chore: update sdk url (#47)

vulet · faustbrian · commit f2f2f3f4e8bc · 2019-05-27T07:01:23.000+02:00
diff --git a/README.md b/README.md
@@ -13,7 +13,7 @@
 
 ## Documentation
 
-You can find installation instructions and detailed instructions on how to use this package at the [dedicated documentation site](https://docs.ark.io/sdk/clients/php.html).
+You can find installation instructions and detailed instructions on how to use this package at the [dedicated documentation site](https://docs.ark.io/sdk/clients/usage.html).
 
 ## Security
 
