Include .gitignore in list of ignored paths

[Kikobeats]

I noted you are ignoring files here: https://github.com/zeit/micro-dev/blob/de0d1b8a8f38651262cf6d00263bda1875751cbc/lib/listening.js#L81

Ideally get the files from .gitignore and use the current setup when .gitignore is not present 😄.

This could be useful: https://github.com/dwyl/ignored

[Kikobeats]

How I did this at https://github.com/Kikobeats/svr/blob/master/bin/watch/get-watch-config.js#L7

• using ignored for get .gitignores files.
• using ignore-by-default to get common ignoring files.
• support pass ignore files from CLI
• add ignores files declared at package.jon