More documentation about how to install Google Optimize

[stretch0]

Is your feature request related to a problem? Please describe.
It is unclear about what needs to be installed to get this library to work.

The docs mention

Using the useGoogleOptimize hook requires that you've installed Google Tag Manager and created Google Optimize test cases.

But clicking that link, there is note that says to use the Optimize js install:

We strongly recommend using the optimize.js installation method as it offers the best performance and is the easiest way to install Optimize.

So what do I need to install to get this to work? GTM or Optimize or both?

Describe the solution you'd like
Please update documentation on readme to describe how to get this working as it appear the linked documentation may have changed without knowing.

Describe alternatives you've considered
N/A

Additional context
N/A

[jaredLunde]

Good question, I'm not sure anymore. This was accurate when I released it. Would happily accept a PR that clarifies.