Change POST to PUT and _security to security for API example (#173453)

## Summary

Just a small Doc Update. In the first example a POST was used and
towards a non existing handle (`_security` instead of `security`)

In the basic license example posted below this one, this is already
correct.

### Checklist

All checked - none applied. 
(Though first PR in this repository, I am sorry if any mistakes were
made. If so - please point them out, will do better next time 😅 )

---------

Co-authored-by: Kibana Machine <[email protected]>

docs/setup/configuring-reporting.asciidoc

@@ -116,7 +116,7 @@ With <<grant-user-access, {kib} application privileges>> enabled in Reporting, y
 NOTE: This link:https://www.elastic.co/guide/en/kibana/current/role-management-api-put.html[API request] needs to be executed against the link:https://www.elastic.co/guide/en/kibana/current/api.html[Kibana API endpoint].
 [source, sh]
 ---------------------------------------------------------------
-POST <kibana host>:<port>/api/_security/role/custom_reporting_user
+PUT <kibana host>:<port>/api/security/role/custom_reporting_user
 {
 	"elasticsearch": {
 		"cluster": [],