Update site-design-json-schema.md (SharePoint#3031)

Author: Seiyasu

docs/declarative-customization/site-design-json-schema.md

@@ -845,7 +845,7 @@ Use the **setRegionalSettings** action to configure the regional settings of the
 
 ## Add users (principals) to SharePoint Groups
 
-Use the **addPrincipalToGroup** action to manage addition of users and groups to select default SharePoint groups. For more information, see [Understanding SharePoint Groups](https://support.office.com/en-us/article/Understanding-SharePoint-groups-94D9B261-161E-4ACE-829E-ECA1C8CD2EB8). This action can be used for licensed users, security groups, and Office 365 Groups.
+Use the **addPrincipalToSPGroup** action to manage addition of users and groups to select default SharePoint groups. For more information, see [Understanding SharePoint Groups](https://support.office.com/en-us/article/Understanding-SharePoint-groups-94D9B261-161E-4ACE-829E-ECA1C8CD2EB8). This action can be used for licensed users, security groups, and Office 365 Groups.
 
 #### JSON values