Updates Zenodo (DOI) (#3949)

* Updates Zenodo (DOI)

The DOI entered will now always resolve tot he newest release. The other DOI was pinned to a specific release.

* Updates with a How to Cite section

* Review comments addressed

* Update README.md

README.md

@@ -4,13 +4,14 @@
 [![Join the discourse at https://astrodiscuss.usgs.gov](https://img.shields.io/discourse/https/astrodiscuss.usgs.gov/topics.svg?style=flat)](https://astrodiscuss.usgs.gov/)
 [![Anaconda-Server Badge](https://anaconda.org/usgs-astrogeology/isis3/badges/version.svg)](https://anaconda.org/usgs-astrogeology/isis3)
 [![Anaconda-Server Badge](https://anaconda.org/usgs-astrogeology/isis/badges/version.svg)](https://anaconda.org/usgs-astrogeology/isis)
-[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.3697216.svg)](https://doi.org/10.5281/zenodo.3697216)
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.2563341.svg)](https://doi.org/10.5281/zenodo.2563341)
 
 ## Table of Contents
 
 * [Requests for Comment](README.md#Requests-for-Comment)
 * [FAQ](README.md#FAQ)
 * [Installation](README.md#Installation)
+* [Citing ISIS](README.md#Citing-ISIS)
 * [Start Contributing](https://github.com/USGS-Astrogeology/ISIS3/wiki/How-to-Start-Contributing)
 * [ISIS Data Area](README.md#The-ISIS-Data-Area)
 * [Installing Older Versions of ISIS](README.md#Installing-older-versions-of-ISIS)
@@ -293,6 +294,9 @@ To build and compile ISIS requires following the instructions listed below, whic
 -   [Building ISIS3 documentation](https://github.com/USGS-Astrogeology/ISIS3/wiki/Developing-ISIS3-with-cmake#building-isis3-documentation)
 -   [What to do if you encounter any problems](https://github.com/USGS-Astrogeology/ISIS3/wiki/Developing-ISIS3-with-cmake#problems)
 
+## Citing ISIS
+This project uses a [Zenodo](https://zenodo.org) generated DOI. The badge at the top of this README links to the DOI for the [latest release](https://doi.org/10.5281/zenodo.2563341). It is [good practice](https://help.zenodo.org) (See 'Which DOI Should I Use in Citations?') to cite the version of the software being used by the citing work. To obtain this DOI, one can follow the [link to the latest version](https://doi.org/10.5281/zenodo.2563341) and then check the right sidebar area titled **Versions** for a listing of all ISIS versions that currently have a Zenodo DOI.
+
 ## The ISIS Data Area
 
 ### Ancillary Data