docs: add atracker service sdk reference url (#141)

Author: Andras-Csanyi

README.md

@@ -46,7 +46,7 @@ The IBM Cloud Platform Services Go SDK allows developers to programmatically int
 
 Service Name | Package name 
 --- | --- 
-Activity Tracker | atrackerv1
+[Activity Tracker](https://test.cloud.ibm.com/apidocs/atracker?code=go) | atrackerv1
 [Case Management](https://cloud.ibm.com/apidocs/case-management?code=go) | casemanagementv1
 [Catalog Management](https://cloud.ibm.com/apidocs/resource-catalog/private-catalog?code=go) | catalogmanagementv1
 [Configuration Governance](https://cloud.ibm.com/apidocs/security-compliance/config?code=go) | configurationgovernancev1