github actions example uses node version 12

[tabcat]

cli/README.md

Line 113 in d6a6afa

node-version: '12'

Is this right? Seems a bit old. Why not use node-version: 'lts/*'?

[tabcat]

Same thing for this line

cli/README.md

Line 108 in d6a6afa

runs-on: ubuntu-16.04