This PR replaces our `console.log` with `nicelog` so that I can more
easily grep for errant console.logs.
### Change Type
- [x] `internal` — Any other changes that don't affect the published
package (will not publish a new version)
We make use of this `exec` function for the new huppy bot. For that, I
needed to support a couple of extra use-cases: extending the `env` used
to evaluate a command, and prefixing the command output with a string.
In use, these look something like this:
```ts
await exec('my', ['command'], {
env: {HELLO: 'world'},
...prefixOutput('my prefix'),
})
```