fix environment file

Author: lmoncla

README.md

@@ -13,6 +13,7 @@ Avian influenza viruses (AIVs) periodically cross species barriers and infect hu
 The notebooks in this repo require `baltic/baltic.py`, which is available from [this GitHub repo](https://github.com/evogytis/baltic). There is a working version in this repo. Every notebook also requires R and ryp2, a package for using R within python jupyter notebooks. To ensure you have all the required packages, do the following: 
 
 1. Install [miniconda](https://docs.conda.io/en/latest/miniconda.html) for your machine. 
+2. Install [R](https://www.r-project.org/) if you do not have it. 
 2. Clone this repo: `git clone https://github.com/blab/h5n1-cambodia`
 3. Create the conda environment: `conda env create -f h5n1-cambodia-environment.yml`
 4. Activate the environment: `conda activate h5n1-cambodia-environment`