Fix "WARN [...] Page's .Hugo is deprecated [..] (#42)
Fix "WARN [...] Page's .Hugo is deprecated [..] (#42)

When rendering the page, a warning  pops up:

```
WARN 2019/07/01 13:38:43 Page's .Hugo is deprecated and will be removed in a future release. Use the global hugo function.
```
digitalcraftsman/hugo-type-theme