// test packages, and all the run actions for these
			// packages will depend on it. Motivating example:
			// supposed we have a top level directory with three
			// package subdirs, "a", "b", and "c", and
			// from the top level, a user runs "go test -coverpkg=./... ./...".
			// This will result in (roughly) the following action graph:
			//
			//	build("a")       build("b")         build("c")

//
// See https://golang.org/ref/mod#go-mod-tidy for more about 'go mod tidy'.
//
// # Make vendored copy of dependencies
//
// Usage:
//
//	go mod vendor [-e] [-v] [-o outdir]
//
// Vendor resets the main module's vendor directory to include all packages
// needed to build and test all the main module's packages.
// It does not include test code for vendored packages.
//