docs: fix pkgdown navbar config (#35)

* docs: fix pkgdown navbar config

* Update _pkgdown.yml

_pkgdown.yml

@@ -1,22 +1,17 @@
 navbar:
-  title: ~
-  type: default
-  left:
-  - text: Reference
-    href: reference/index.html
-  - text: Articles
-    menu:
-    - text: JOSS paper
-      href: https://joss.theoj.org/papers/10.21105/joss.00056
-    - text: Abstract/Poster presented at AGU 2014
-      href: http://adsabs.harvard.edu/abs/2014AGUFM.H13H1209V
-    - text: Vignette
-      href: articles/index.html
-  - text: News
-    href: news/index.html
-  right:
-  - icon: fa-github fa-lg
-    href: https://github.com/ropensci/hddtools/
+  structure:
+    left:  [intro, reference, articles, tutorials, news]
+    right: [search, github, lightswitch]
+  components: 
+    articles:
+      text: Articles
+      menu:
+        - text: JOSS paper
+          href: https://joss.theoj.org/papers/10.21105/joss.00056
+        - text: Abstract/Poster presented at AGU 2014
+          href: http://adsabs.harvard.edu/abs/2014AGUFM.H13H1209V
+        - text: Vignette
+          href: articles/index.html
 
 reference:
 - title: Get catalogues