Update Codebase getting-started guide

THis MR updates the Sign-In section of the Codebase getting-started guide.

docs/software/gitlab/getting-started.md

@@ -12,20 +12,24 @@ With the general availability of the Helmholtz Cloud,
 the service will be available as a fully integrated Helmholtz Cloud Service
 and will follow the given regulations.
 
-## Sign-Up
+## Sign-In
 
 ### Available Options
 
-Multiple options exist to sign-in the Helmholtz coding platform.
+Multiple options exist to sign in to the Helmholtz coding platform.
 
 * **Helmholtz AAI:** This is the recommended login method for everyone except
   HZDR employees.
-  Please note, that the Helmholtz AAI also supports the social providers
-  _Google_, _GitHub_ and _Orcid_. 
+!!! success "Please note"
+    In addition to a variety of scientific and university institutions, the Helmholtz AAI also supports the social
+    providers **Google**, **GitHub** and **ORCID**. 
 * **HZDR LDAP:** :fontawesome-solid-triangle-exclamation: Only HZDR employees can use this method.
-* **GitHub (Deprecated):** :fontawesome-solid-triangle-exclamation: This method is still available for
-  historical reasons and **will be removed on September 1st, 2022**. It is recommended to use the Helmholtz AAI instead.
-!!! info "Switching to Helmholtz AAI login method"
+* **GitHub (Deprecated):** :fontawesome-solid-triangle-exclamation: This method **was removed on September 1st, 2022**.
+  It is recommended to use the Helmholtz AAI instead.  
+  If you can no longer log in, please contact us by mail to
+  [support@hifis.net](mailto:support@hifis.net?subject=%5BGitLab%5D%3A%20Deprecated%20GitHub%20login) or create a ticket
+  in the HIFIS Helpdesk at [support.hifis.net](https://support.hifis.net/).
+!!! info "Switching to Helmholtz AAI from any other login method"
     Please open your GitLab [account settings :fontawesome-solid-up-right-from-square:](https://gitlab.hzdr.de/-/profile/account)
     and choose *"Connect Helmholtz AAI"* inside the *Social Sign-in* section. After successful login with the Helmholtz
     AAI, you can disconnect from GitHub by choosing *"Disconnect GitHub"* in the previously mentioned *Social Sign-in* section.