docs: alternative for local `karma-cli` install

[kevireilly]

While installing karma-cli globally may commonly make some sense, another alternative is keeping it encapsulated within each individual repository which is also easy enough.

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[anthony-redFox]

Hi, the project karma-cli is closed, I don't think that need to push people to use old project.