Local version supported?

Ideally I don't want to install this globally so I installed against a single repo and ran:

`npx bump patch ./app-version.json`

But that just changed my `package.json` version to "patch"

I've also tried `npx bump --patch app-version.json` but can't seem to find the right combination of arguments to update my custom file.

`app-version.json`:

```
{
  "version": "2.0.5"
}
```