Add a section about Pages in "Configure GitHub"

There is no particular configuration needed, but users might look for
that info in this section, so we just point them to the proper section.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

docs/user-guide/start-a-new-project/configure-github.md

@@ -155,3 +155,9 @@ Import the following
 
 The basic code configuration should be generate using
 [repo-config](https://frequenz-floss.github.io/frequenz-repo-config-python/).
+
+## GitHub Pages
+
+No special configuration is needed for GitHub Pages, but you need to initialize
+the `gh-pages` branch. You can read how to do this in the [Initialize GitHub
+Pages](index.md#initialize-github-pages.md) section.