Update snap for Ubuntu

[taylor.smock]

This may be a major source of duplicates for #14596. I'll have to look into updating the snap for current "best practices".

taylor.smock wrote in comment 67 of #14596:

Replying to cserpell@…:

In Ubuntu 22.04, I noticed this started happening when I started using jOSM from snap version, instead of deb version from repository. I didn't change any option by myself, just the defaults.

Thank you for this response.

It gives us a place to start debugging why this problem keeps happening.

1. The snapcraft (see source:trunk/native/snapcraft.yaml​) does not use the start script from source:trunk/native/linux/tested/etc/default/josm​. This means that some required start arguments are not added. I don't know if we can use the start script (is JavaFX built into the snap? I don't know, and we kind of require javafx in the start script right now, mostly to avoid bug reports from Microsoft Streetside).
2. It looks like we haven't really changed the snapcraft.yml file in 5 years, give or take. Are we even following best practices for snaps any more?

I'll see if I can figure out how to build the snap, and then I'll see if I can make the modifications for it.

[skyper]

Is Ubuntu package the correct component?
Maybe, ​Michael Vogt (mvo), publisher of the josm snap at Canonical Snapcraft, can help here.