Fix support for submodules

[mohd-akram]

Closes #15

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[jsumners]

Can you add a test for this?

[mohd-akram]

Not sure how to go about this...there don't seem to be any tests for the install script.

[mohd-akram]

Any update on this?

[jsumners]

I'd like to see a test. An integration test is acceptable.

[Uzlopak]

@mohd-akram

Dont get me wrong: Did you close this because you dont want to provide a test?

[mohd-akram]

This is not that big of a priority for me, and I'm not currently using this fork (I'm using the original pre-commit module but that isn't maintained). Someone has to figure out how to add install tests to the repo and integrate it with the CI.