I think it's nice to have a place to keep around things that are
relevant, but not necessarily accurate anymore. We could also expand
this to actually describe the history of depot, but I lack the context
for that as I haven't been around from the beginning.
We may want to redirect the link from README to the monorepo doc here.
Change-Id: I971f4ab873a66ba66719a0795d86b4de0e32d32b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/13039
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
