Article links do not work on pkgdown website

[peterdesmet]

Reported by @hansvancalster, articles/tutorials referenced in navbar lead to 404:

• https://inbo.github.io/inborutils/articles/guess_projection.html
• https://inbo.github.io/inborutils/articles/reference/articles/gbif_name_match.html
• https://inbo.github.io/inborutils/articles/reference/articles/articles/data_loaders_examples.html

[peterdesmet]

Fixed with cac059f (see https://travis-ci.community/t/deployment-of-pages-with-r-travis-fails-with-pkgdown-when-vignettes-includes-the-current-package/2048/2 for details)

I've also used the default navbar + article section in _pkgdown.yml: 9a0388c + added URL and issues URL: 3ab521f

[hansvancalster]

👍 Thanks for fixing this!