Add Extrusion release notes

[lynn-lumen]

Objective

• Fixes Write release notes for PR #13270: Extrusion #1312

Additional informarion

• There are several places in these release notes where it would make sense to link to docs.rs or similar resources. However, the resources neededn (e.g. the ShapeSample trait) do not exist there yet. Should I just guess the future link or should this be added later?
• I have referred to a custom primitive to demonstrate some points in the release notes. Should an example containing a "complete" implementation of a custom primitive exist?

[alice-i-cecile]

Link to https://dev-docs.bevyengine.org/bevy/index.html for now: we'll swap the links over in editing passes in the last round :)

[alice-i-cecile]

As for the custom primitives, I think I'd be happy to see an example for that (the heart is cute!), but I definitely won't block on it.