cmd/go: 'go list' should support -u=patch

[jerome-laforge]

Background

Currently, it is not possible to list available update module only for patch.
For example:

module github.com/test/test

go 1.15

require go.mongodb.org/mongo-driver v1.3.6

I want to know if a new patch version if available (here v1.3.7 and not v1.4.0), but I don't know how to do.
The given example here https://github.com/golang/go/wiki/Modules#how-to-upgrade-and-downgrade-dependencies is for direct with minor and patch (I just want patch). And yet, the v1.3.7 has been released (https://pkg.go.dev/mod/go.mongodb.org/mongo-driver@v1.3.7).

$ go list -u -m all | grep "go.mongodb.org/mongo-driver"
go.mongodb.org/mongo-driver v1.3.6 [v1.4.0]

Description

I propose to add -u=patch (as already proposed for go get)

$ go list -u=patch -m all | grep "go.mongodb.org/mongo-driver"
go.mongodb.org/mongo-driver v1.3.6 [v1.3.7]

[bcmills]

CC @jayconrod @matloob

Honestly, I'm surprised that list doesn't already support -u=patch. (I think we should just do this — no need for a formal proposal.)

[gopherbot]

Change https://go.dev/cl/432536 mentions this issue: cmd/go: add -u=patch option for go list

[goto1134]

@bcmills , seems like the review is stuck on waiting for your reply. Could you come back to it when it'll be convenient for you?