feat: set app version as dev when building locally

[setchy]

A small enhancement to help when doing local development remember which version of the app is running 😎

[bmulholland]

Good idea. Could also consider changing a key color, like the sidebar background, so it's hard to miss

[afonsojramos]

Would also be nice to have "demo notifications" so that we don't need to load real ones 🤔

[setchy]

I have a stash locally that mocks the API response. Could add that into the scope of #980 or as a separate idea (probably better separately)

[setchy]

A while ago I was using https://github.com/setchy/gitify-notifications-sandbox too, which could be transferred into the gitify-app organization if we wanted "real" notifications

[afonsojramos]

I suppose there's the two cases, the ones where we just want to work with UI, and the cases where we need to work with the flow themselves.