main.go가 빌드가 안됩니다.

guru@docker:~$ go get github.com/julienschmidt/httproutergo: 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'.