Various dependencies, including "golang.org/x/.." started to update
the minimum required version,so we should follow suit for the next
release.
Note that the `//go:build` directives not necesserily have to be
updated, but it's good to keep them in sync until we have a go.mod
to control this.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Use the same script as is used in moby/moby, which more gracefully
handles an existing `go.mod` (which can be symlinked) into account.
- keep the scripts called generic, and update the Makefile to invoke
them with the "with-go-mod.sh" script.
- use "go run" instead of building temporary binaries
- check if go-md2man exists before building a binary
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
