Update modules/authentication/proc-enabling-user-authentication-with-github.adoc

Fixes https://issues.redhat.com/browse/RHIDP-7635

Author: themr0c

modules/authentication/proc-enabling-user-authentication-with-github.adoc

@@ -7,6 +7,7 @@ To authenticate users with GitHub, configure the GitHub authentication provider
 * You link:{configuring-book-url}[added a custom {product-short} application configuration], and have sufficient permissions to modify it.
 
 * You have sufficient permissions in GitHub to create and manage a link:https://docs.github.com/en/apps/overview[GitHub App].
+Alternatively, you can ask your GitHub administrator to prepare the required GitHub App.
 
 .Procedure
 . To allow {product-short} to authenticate with GitHub, create a GitHub App.