[release-1.3] chore(broken link): fix link to https://github.com/janus-idp/backstage-showcase/blob/main/docs/auth.md#enabling-authentication-in-showcase RHIDP-4294 (#571)

Co-authored-by: RHDH Build (rhdh-bot) <[email protected]>

Author: openshift-cherrypick-robot

modules/getting-started/proc-adding-github-to-frontend.adoc

@@ -12,4 +12,4 @@ signInPage: github
 .Additional resources
 
 * For information about authenticating Backstage access with GitHub, see link:https://backstage.io/docs/integrations/github/github-apps/[GitHub Authentication Provider] in the community documentation. 
-* For information about adding the provider to the Backstage front end, see link:https://github.com/janus-idp/backstage-showcase/blob/main/showcase-docs/getting-started.md[Enabling authentication in Showcase] in the community documentation. 
+* For information about adding the provider to the Backstage front end, see link:https://github.com/janus-idp/backstage-showcase/blob/main/docs/auth.md#enabling-authentication-in-showcase[Enabling authentication] in the community documentation.