AppData section doesn't mention release tags

[danirabbit]

What Happened?

Some developers have submitted their apps without release tags, likely because we don't mention it in the dev guide.

Steps to Reproduce

Go here: https://docs.elementary.io/develop/writing-apps/our-first-app#appdata.xml

See that the docs don't mention release tags

Expected Behavior

We should revisit the section on metadata to make sure it mentions all the required tags included releases.

https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-releases

OS Version

6.x (Odin)

Software Version

Latest release (I have run all updates)

Log Output

No response

Hardware Info

No response