ref: https://cobra.dev/docs/tutorials/getting-started/
Between step 2 and step 3 the cobra-cli command does not create a go.mod file in the generated folder automatically. I needed to run go mod init, go mod tidy, and update the import line in the main.go file to contain the newmodulename/cmd and everything then complied/ran correctly.
I don't mind making a PR and updating the docs if it's a documentation issue but this seems more like a potential bug in the cobra-cli command itself.