Add links to official docs site.

For more details: https://ropensci.org/technotes/2019/06/07/ropensci-docs/

Author: ropenscibot

DESCRIPTION

@@ -10,7 +10,7 @@ Description: Experimenting with computer vision and machine learning in R. This
     static images, or to filter live video footage from a camera device.
 License: MIT + file LICENSE
 SystemRequirements: OpenCV: libopencv-dev (Debian, Ubuntu) or opencv-devel (Fedora)
-URL: https://opencv.org (upstream) https://github.com/ropensci/opencv (devel)
+URL: https://docs.ropensci.org/opencv,  https://opencv.org (upstream) https://github.com/ropensci/opencv (devel)
 BugReports: https://github.com/ropensci/opencv/issues
 LinkingTo: Rcpp
 Imports: Rcpp, magrittr