Update boost link to be https

Author: jimhester

vignettes/cpp11.Rmd

@@ -635,7 +635,7 @@ The standard template library (STL) provides a set of extremely useful data stru
 This section will explain some of the most important algorithms and data structures and point you in the right direction to learn more.
 I can't teach you everything you need to know about the STL, but hopefully the examples will show you the power of the STL, and persuade you that it's useful to learn more.
 
-If you need an algorithm or data structure that isn't implemented in STL, one place to look is [boost](http://www.boost.org/doc/).
+If you need an algorithm or data structure that isn't implemented in STL, one place to look is [boost](https://www.boost.org/doc/).
 Installing boost on your computer is beyond the scope of this vignette, but once you have it installed, you can use boost data structures and algorithms by including the appropriate header file with (e.g.) `#include <boost/array.hpp>`.
 
 ### Using iterators