package/go: security bump to version 1.16.4

package/go: security bump to version 1.16.4

Fixes the following security issues:

- CVE-2021-31525: ReadRequest and ReadResponse in net/http can hit an
  unrecoverable panic when reading a very large header (over 7MB on 64-bit
  architectures, or over 4MB on 32-bit ones).  Transport and Client are
  vulnerable and the program can be made to crash by a malicious server.
  Server is not vulnerable by default, but can be if the default max header
  of 1MB is overridden by setting Server.MaxHeaderBytes to a higher value,
  in which case the program can be made to crash by a malicious client.

  https://github.com/golang/go/issues/45710

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>