Go build instructions don't work

[lpar]

Trying to install using go install as mentioned in the README:

> go install github.com/johnkerl/miller/cmd/mlr
go: 'go install' requires a version when current directory is not in a module
	Try 'go install github.com/johnkerl/miller/cmd/mlr@latest' to install the latest version
> go install github.com/johnkerl/miller/cmd/mlr@latest
go: github.com/johnkerl/miller/cmd/mlr@latest: module github.com/johnkerl/miller@latest found (v5.10.3+incompatible),
  but does not contain package github.com/johnkerl/miller/cmd/mlr