[dev.cmdgo] cmd/go: add go mod editwork command

[dev.cmdgo] cmd/go: add go mod editwork command

go mod editwork behaves similarly to go mod edit:
it has flags to change the go version, and add and remove
directory and replace directives.

For #45713
Change-Id: I1c795c122bfe461d6e87dd731692e0bf1bbe2bf7
Reviewed-on: https://go-review.googlesource.com/c/go/+/334938
Trust: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>