Adds npm install steps to publish workflow

[TysonMN]

Resolves #20
...for reals this time ;)

The publish workflow needs install steps. After I added these install steps, the workflow passed for me. Still not sure if it will successfully publish a new version when it is supposed to. As I described in #22 (comment), I have successfully tested this workflow.

[loreanvictor]

P.s. the reason this is not merged is that I'm giving the concept a bit more test on some other (more experimental) packages to see how it fairs. So far, I can say:

• I opted for using this action instead, since it seems to work better when you DO NOT want to have an additional check for some release message in the commit message. That workflow seems more streamlined to me since there is no magic anywhere in it and every bump in package.json simply means a new version is going to be published.

• The workflow works pretty well when the package has tests (since it can simply stop if the tests are not passing, better yet you could even fail the publish if coverage is for example below a certain threshold). This package unfortunately does not (yet) have any tests, which makes it a bit more risky to do accidental automated publishes. That said, I still find myself making a separate commit for each publish when I am sure everything is ready, so perhaps thats not an issue.

I will use the same workflow on some bigger packages soon to see how things go, but it seems like a pretty convenient thing (since generally each new version DOES need at least one commit and then some other manual work).

[TysonMN]

Sounds good to me. I don't have any particular affinity for the Publish to npm action. I think it is just the first one that I found.