bug: update script attribute

[MartinMa]

Closes #184

- Summary
Apparently hugo outputs main.js, not app.js anymore. So I updated the template accordingly. See linked issue.

[MartinMa]

Actually, I have to revoke this pull request!

Now I have main.js twice locally:

And this in the production version:

I don't know what's going on.

[erquhart]

You should be able to just remove that script tag from the footer, the scripts are injected here: https://github.com/netlify-templates/one-click-hugo-cms/blob/master/site/layouts/_default/baseof.html#L14

[MartinMa]

@erquhart Thanks for the answer! Can I remove the file app.js altogether? Its contents don't seem to be compiled into the bundle. The entry point seems to be index.js.