This gets us the zlib-flate command line utility, which is useful for
decompressing our zlib-compressed save files and poking around in the
JSON
Change-Id: Ia0d8259d261c4313322d68cc8409ba13f9fb570c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3217
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI