docs: Add a note for GitHub SSH scheme (#1089)

Co-authored-by: Cem Aksoylar <caksoylar@users.noreply.github.com>

docs/docs/user-setup.md

@@ -143,6 +143,10 @@ GitHub Repo: https://github.com/petejohanson/zmk-config.git
 
 Only the GitHub username is required; if you are happy with the defaults offered in the square brackets, you can simply hit `Enter`.
 
+:::note
+If you are using SSH keys for git push, change GitHub Repo field to the SSH scheme, e.g. `git@github.com:petejohanson/zmk-config.git`.
+:::
+
 ### Confirming Selections
 
 The setup script will confirm all of your selections one last time, before performing the setup: