Fighting the browser cache in deployed websites

[rallisf1]

Is your feature request related to a problem? Please describe.
Many browsers (especially chrome mobile) don't respect the caching TTL set by hosts. This leads to changes made in existing symbols to not be visible by guests, even after that TTL, unless they clear their browser history.

Describe the solution you'd like
Add the build time timestamp as a file suffix on exported _symbols.

Describe alternatives you've considered
I am currently either duplicating symbols, so their id changes, which is not that helpful when being used in many pages; or setting a no-cache, no-store, must-revalidate Cache-Control header on the host.