adjust pkgdown figure width

Author: ctoney

_pkgdown.yml

@@ -41,5 +41,5 @@ external-articles:
   href: https://www.fs.usda.gov/rm/pubs/rmrs_p056/rmrs_p056_53_toney.pdf
 
 figures:
-  fig.width: 6
-  fig.height: 6
+  fig.width: 6.2
+  fig.height: 6.2