'go get' is no longer supported outside a module

[T-recks]

Following these instructions, when I run make I get this error:

[trecker@localhost ~]$ cd devtools-main/
[trecker@localhost devtools-main]$ make
go get gopkg.in/yaml.v2
go: go.mod file not found in current directory or any parent directory.
'go get' is no longer supported outside a module.
To build and install a command, use 'go install' with a version,
like 'go install example.com/cmd@latest'
For more information, see https://golang.org/doc/go-get-install-deprecation
or run 'go help get' or 'go help install'.
make: *** [Makefile:18: .go-setup] Error 1