Merge pull request #3306 from balena-io/add-extra-firmware-nav

Add extra-firmware page to sidebar navigation

Author: flowzone-app[bot]

config/navigation.txt

@@ -41,6 +41,7 @@ Learn
     [/learn/develop/multicontainer]
     Develop with Apps[/learn/develop/apps]
     [/learn/develop/blocks]
+    [/learn/develop/extra-firmware]
     [/learn/develop/runtime]
     [/learn/develop/hardware]
       [/learn/develop/hardware/gpio]