Update security_checker.rst

Author: shreypuranik

security/security_checker.rst

@@ -25,6 +25,14 @@ FriendsOfPHP organization.
     This way you can add it to your project build process and your continuous
     integration workflows to make them fail when there are vulnerabilities.
 
+.. tip::
+
+    Earlier versions of this command used a tool hosted at a now deprecated URL,
+    with the tool having since been moved to a new location, which has been 
+    reflected in newer versions of the bundle. Use the latest version of the 
+    command to avoid getting exit code zero and breaking existing build plans
+    if the command has been integrated into project build process.
+    
 .. note::
 
     To enable the ``security:check`` command, make sure the