DOC: Update documentation

CONTRIBUTING.md

@@ -7,6 +7,8 @@ We love to have your contributions to the GraphBin project, whether it's:
 
 ## Clone and install GraphBin onto your machine
 
+First, make sure you have [git](https://github.com/git-guides/install-git) installed on your machine.
+
 On GitHub, [fork](https://docs.github.com/en/get-started/quickstart/fork-a-repo) the GraphBin repository and [clone](https://docs.github.com/en/repositories/creating-and-managing-repositories/cloning-a-repository) it to your machine.
 
 ```

README.md

@@ -16,9 +16,9 @@
 
 ## Dependencies
 
-GraphBin installation requires python 3 (tested on Python 3.6 and 3.7). The following dependencies are required to run GraphBin and related support scripts.
-* [python-igraph](https://igraph.org/python/) - version 0.7.1
-* [biopython](https://biopython.org/) - version 1.74
+GraphBin installation requires python 3 to run. The following dependencies are required to run GraphBin and related support scripts.
+* [python-igraph](https://igraph.org/python/)
+* [cogent3](https://cogent3.org/)
 * [cairocffi](https://pypi.org/project/cairocffi/)
 
 ## Installing GraphBin
@@ -40,7 +40,7 @@ graphbin -h
 
 ### Using pip
 
-You can install GraphBin using pip.
+You can install GraphBin using [pip](https://pypi.org/project/graphbin/).
 
 ```
 pip install graphbin