[doc] fix link to stsafe-a120-sdk

Author: Grom-

README.md

@@ -62,7 +62,7 @@ Reference implementation for most common STSE applicative use case can be found
 Following applicative project can be used as reference for STSELib integration and usage.
 
 - STSAFE-A
-    - [stsafe-a-sdk](https://github.com/STMicroelectronics/STSAFE-A120_sdk) 
+    - [stsafe-a-sdk](https://github.com/STMicroelectronics/STSAFE-A120-sdk) 
     - [wolfssl-examples](https://github.com/wolfSSL/wolfssl-examples/tree/master/stsafe) developed and maintained by [WolfSSL](https://www.wolfssl.com/) 
     - [Zephyr_st-stsafe-a1xx](https://github.com/catie-aq/zephyr_st-stsafe-a1xx) developed and maintained by [CATIE](https://www.catie.fr/language/en/home/)