Add options for the pants-init action

[bryanwweber]

This adds options for:

• Configuring the cache location on the runner
• Configuring the GH_HOST for enterprise instances

It also does a little cleanup on some of the other steps. @jsirois encouraged me to submit this after this conversation on Slack

[kaos]

Thanks. lgtm overall bar the typos ;)

[bryanwweber]

Thanks for catching the typos @kaos! I just commited your suggestions, so should be all good now.

[kaos]

lgtm.

I'd prefer a second pair of eyes though, as I'm not that familiar with GH actions.

[benjyw]

I assume you've manually tested this, and are sure that the GH_TOKEN change is good?

[cognifloyd]

This is great. Making the cache paths configurable is superb, and cleaning up the if: statements and the use of runner.temp is excellent.

I'm concerned about injecting GH_TOKEN into GITHUB_ENV however, and I've left a comment about that.

Also I had a couple other minor questions.

[bryanwweber]

@cognifloyd Thanks for the review! I confirmed the changes worked with thegh-host input set, so I think it's good to go. Thanks!

[cognifloyd]

That looks better. Thanks for testing my suggestion -- I'm glad it worked!