Fix no-unused-vars for variables assigned to in template but only used in script

[Conduitry]

Fixes #64.

It's been a while since I looked at this code though, and I want to let this sit for a bit before merging, so I can be more sure this is how I want to handle this.

[Conduitry]

Hm the test failure is because this lists eslint@>=6.0.0 as a devdep, and ESLint 7 no longer works on Node 8. I'd rather not just drop Node 8 from the support/testing matrix. I guess I'll sit on this decision as well.

[NicoCevallos]

@Conduitry check what I did in the file .github/workflows/ci.yml in this PR #62 to remove test over Node 8 and adding version 14

[benmccann]

I think @Conduitry knows how to update ci.yml. The question is whether we should:

I'd rather not just drop Node 8 from the support/testing matrix.

[NicoCevallos]

Sure, I didn't want to offend anybody with my comment...

Another option could be to publish one version to support newer versions of Node and ESLint, and another to continue supporting Node 8 if it's required. In my comment I mentioned what I did to don't break Node 8 tests, but that limits to install only ESLint 6.x.x

[benmccann]

Node 8 support was dropped in #77, so hopefully the tests should pass if you rebase this