Update CONTRIBUTING.md
Added clarity to updating conda- I read it as meaning the specific version of conda
@@ -148,7 +148,7 @@ To update one of the dependencies shared across all `repo2docker` builds, you
must follow these steps (with more detailed information in the sections below):
* Make sure you have [Docker](https://www.docker.com/) running on your computer
-* Bump the version number in the `conda` environment ([link](https://github.com/jupyter/repo2docker/blob/master/CONTRIBUTING.md#conda-dependencies))
+* Bump the version numbers of the dependencies you want to update in the `conda` environment ([link](https://github.com/jupyter/repo2docker/blob/master/CONTRIBUTING.md#conda-dependencies))
* Make a pull request with your changes ([link](https://github.com/jupyter/repo2docker/blob/master/CONTRIBUTING.md#make-a-pull-request))
See the subsections below for more detailed instructions.
