This was quite hairy. The best approach I came up with is to use `git`'s
last modified date. But Vercel uses a shallow clone, so the file's
modification date isn't preserved.
Luckily, I found an undocumented ENV var, `VERCEL_DEEP_CLONE` that fixes
this when set to `true`.
Using this technique we can generate any file's modified timestamp and
load it from a server component to render.
Fixes#3960
<img width="321" alt="Screenshot 2024-04-10 at 11 11 49 PM"
src="https://github.com/firezone/firezone/assets/167144/07fe89cd-d792-49ca-b25b-8472fa19de8b">
