Update README to include info about CRAN support (#458)

README.md

@@ -21,7 +21,8 @@ The main goal of this project is to generate concise recipes
 for [conda-forge](https://conda-forge.org/).
 The Grayskull project was created with the intention to eventually replace `conda skeleton`. <br>
 Presently Grayskull can generate recipes for Python packages available on PyPI and also those not published on PyPI but available as GitHub repositories.
-Future versions of Grayskull will support recipe generation for packages of other repositories such as CRAN and Conan etc..
+Grayskull can also generate recipes for R packages published on CRAN.
+Future versions of Grayskull will support recipe generation for packages of other repositories such as Conan and CPAN etc..
 
 ## Installation
 
@@ -45,7 +46,7 @@ pip install -e .
 ## Usage
 
 It is pretty simple to use `grayskull`. Just call it, pass the repository
- (just `pypi` for now) and the package name.
+ (`pypi` or `cran`) and the package name.
 
 * Example:
 ```bash