CL waiting on review for 2.5 years

[Caleb Spare]

Hi,

Could someone review https://go.dev/cl/218620 ("ssh: support for
marshaling keys using the OpenSSH format")? This is a CL that has been
open and waiting since February 2020. It has gotten a few drive-by
reviews from community members but it needs a review from an x/crypto
approver.

This CL corresponds to a proposal (https://go.dev/issue/37132) which
was approved in March 2020. So it also represents something of a
breakdown in the proposal process:

* The community member sent a proposal accompanied by a CL
* The proposal was discussed and promptly approved
* The PR sat for 2.5 years with no action

It's kind of meaningless to accept a proposal if we're not going to
review the CL.

Caleb