Update to last hugo version

[guilhermebr]

Works only with 0.31 or below

[vdemario]

This may be related or not.

When I try to run the en-US version of the website the css is not applied, Chrome complains about the MIME type, it's going out as text/plain.

It's likely Hugo has already fixed this but not on 0.31. It doesn't affect production probably because of Caddy.