docs: fix documentation sdk url (#68)

Author: vmunich

README.md

@@ -26,7 +26,7 @@ If you have any questions, requests or ideas open an issue or ask us in #python
 
 ## Documentation
 
-You can find installation instructions and detailed instructions on how to use this package at the [dedicated documentation site](https://docs.ark.io/api/sdk/cryptography/python.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/cryptography/python.html).
 
 ## Security