update pkgdown option

README.md

 # biodivMapR: an R package for α- and β-diversity mapping using remotely-sensed images
+
+**[https://jbferet.github.io/biodivMapR](https://jbferet.github.io/biodivMapR/index.thml)**
+
 ![licence](https://img.shields.io/badge/Licence-GPL--3-blue.svg)
 [![Build Status](https://travis-ci.org/jbferet/biodivMapR.png?branch=master)](https://travis-ci.org/jbferet/biodivMapR)
 

vignettes/tutorial.Rmd

@@ -5,8 +5,8 @@ date: "`r Sys.Date()`"
 output: 
   html_vignette:
     number_sections: true
-  pkgdown:
-    number_sections: true
+pkgdown:
+  as_is: true
 vignette: >
   %\VignetteIndexEntry{Tutorial}
   %\VignetteEngine{knitr::rmarkdown}