feat: prompt user to reload when updates available

[olizilla]

When the service worker finds updates, tell the user and ask them to reload.

License: MIT
Signed-off-by: Oli Evans oli@tableflip.io

[olizilla]

Tricky to test this one without setting up local https. create-react-app sets up a service worker so the app works offline, but this leads to surprising behaviour where you don't get the latest version until you reload the page. With this PR we tell the user, rather than hope they guess.

We'll want something similar for webui. It's questionable if we want a service worker caching webui if it is intended to be hosted from a ipfs daemon, but as @lidel points out we want the app to work well in all scenarios.

[victorb]

Oh, nice! Slightly unrelated thought, could we somehow get this into a reusable module that can also be used for sites that are loaded via /ipfs/ but with a hardcoded ipns key that the update can be checked from? Then people can still bookmark the immutable version, but get notifications about updates via ipns.

[hacdias]

lgtm 😄

[olizilla]

@victorbjelkholm cool idea! I think we'll want something like that for the webui.