Adds a command to run go mod edit -go to allow
users to easily upgrade their go directive.
Doing this change also revealed that changing
the go directive does not invalidate the type check
data and there may be stale diagnostics for a package.
Updates golang/go#51086
Change-Id: I659a216059c489a88e29cd51b944c3a0274f3700
Reviewed-on: https://go-review.googlesource.com/c/tools/+/386875
Trust: Suzy Mueller <suzmue@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>