fix broken link in README

README.md

@@ -47,13 +47,13 @@ histogram(randn(10000))
 "backends", where ``GR`` seems to be one of the favorite ones.
 To get an impression how complex visualizations may become
 easier with [Plots](https://juliaplots.github.io), take a look at
-[these](http://docs.juliaplots.org/latest/examples/gr/)  examples.
+[these](https://docs.juliaplots.org/latest/generated/gr/)  examples.
 
 ``Plots`` is great on its own, but the real power comes from the ecosystem surrounding it. You can find more information
-[here](http://docs.juliaplots.org/latest/ecosystem/).
+[here](https://docs.juliaplots.org/latest/ecosystem/).
 
 ## Alternatives
 
 Besides ``GR`` and ``Plots`` there is a nice package called [GRUtils](https://github.com/heliosdrm/GRUtils.jl) which provides a user-friendly interface to the low-level ``GR`` subsytem, but in a more "Julian" and modular style. Newcomers are recommended to use this package. A detailed documentation can be found [here](https://heliosdrm.github.io/GRUtils.jl/stable/).
 
-``GR`` and ``GRUtils`` are currently still being developed in parallel - but there are plans to merge the two modules in the future.
+``GR`` and ``GRUtils`` are currently still being developed in parallel - but there are plans to merge the two modules in the future.