Merge pull request #2015 from agmckee/update-after-installation

Direct user to follow the upgrade steps after installation

Author: jim-parry

user_guide_src/source/installation/installing_composer.rst

@@ -48,6 +48,8 @@ A sample such installation command, using the default project-root "appstarter":
 
     composer create-project codeigniter4/appstarter -s beta --no-dev
 
+After installation you should follow the steps in the "Upgrading" section.
+
 Upgrading
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