update latest release in README

README.md

@@ -1,6 +1,6 @@
 | **Status** | [![Travis build](https://img.shields.io/travis/openforcefield/openforcefield/master.svg?logo=linux&logoColor=white)](https://travis-ci.org/openforcefield/openforcefield) [![Codecov coverage](https://img.shields.io/codecov/c/github/openforcefield/openforcefield.svg?logo=Codecov&logoColor=white)](https://codecov.io/gh/openforcefield/openforcefield) [![LGTM analysis](https://img.shields.io/lgtm/grade/python/g/openforcefield/openforcefield.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/openforcefield/openforcefield/context:python) |
 | :------ | :------- |
-| **Latest Release** | [![Last release tag](https://img.shields.io/github/release-pre/openforcefield/openforcefield.svg)](https://github.com/openforcefield/openforcefield/releases)  [![Commits since release](https://img.shields.io/github/commits-since/openforcefield/openforcefield/0.2.1.svg)](https://github.com/openforcefield/openforcefield/releases/tag/0.2.1)  [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.597754.svg)](https://doi.org/10.5281/zenodo.597754) |
+| **Latest Release** | [![Last release tag](https://img.shields.io/github/release-pre/openforcefield/openforcefield.svg)](https://github.com/openforcefield/openforcefield/releases)  [![Commits since release](https://img.shields.io/github/commits-since/openforcefield/openforcefield/0.5.1.svg)](https://github.com/openforcefield/openforcefield/releases/tag/0.5.1)  [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.597754.svg)](https://doi.org/10.5281/zenodo.597754) |
 | **Communication** | [![docs latest](https://img.shields.io/badge/docs-latest-5077AB.svg?logo=read%20the%20docs)](https://open-forcefield-toolkit.readthedocs.io/en/latest/) [![dev chat on slack](https://img.shields.io/badge/dev_chat-on_slack-808493.svg?logo=slack)](https://join.slack.com/t/openforcefieldgroup/shared_invite/enQtNjA4MTMxMDg0MDAxLWY3Y2Q5NDY4MmU1OTIzMDhiYzFjOWFkZGFjN2Y4N2Q4OTRkOWNjODVhMDMxMzkwMDcxNDA5MjYyNjJjYjE2NTM) |
 | **Foundation** | [![license](https://img.shields.io/github/license/openforcefield/openforcefield.svg)](https://opensource.org/licenses/MIT) [![platforms](https://img.shields.io/badge/Platforms-Linux%2C%20MacOS-orange.svg)](https://open-forcefield-toolkit.readthedocs.io/en/latest/installation.html) [![python](https://img.shields.io/badge/python-3.6%2C%203.7-blue.svg)](https://open-forcefield-toolkit.readthedocs.io/en/latest/installation.html) [![Funding](https://img.shields.io/badge/Funding-Open%20Force%20Field%20Consortium-brightgreen.svg)](http://openforcefield.org) |
 | **Installation** | [![Releases](https://img.shields.io/badge/obtain-latest-green.svg)](https://github.com/openforcefield/openforcefield/releases) [![Conda](https://img.shields.io/conda/v/omnia/openforcefield.svg)](https://anaconda.org/omnia/openforcefield) [![Last updated](https://anaconda.org/omnia/openforcefield/badges/latest_release_relative_date.svg)](https://anaconda.org/omnia/openforcefield) [![Anaconda Cloud downloads](https://anaconda.org/omnia/openforcefield/badges/downloads.svg)](https://anaconda.org/omnia/openforcefield) |