add release, and HW badges (#146)

Co-authored-by: Michael Kochell <6913320+mickmister@users.noreply.github.com>

README.md

@@ -2,6 +2,8 @@
 
 [![Build Status](https://img.shields.io/circleci/project/github/mattermost/mattermost-plugin-mscalendar/master.svg)](https://circleci.com/gh/mattermost/mattermost-plugin-mscalendar)
 [![Code Coverage](https://img.shields.io/codecov/c/github/mattermost/mattermost-plugin-mscalendar/master.svg)](https://codecov.io/gh/mattermost/mattermost-plugin-mscalendar)
+[![Release](https://img.shields.io/github/v/release/mattermost/mattermost-plugin-mscalendar)](/~https://github.com/mattermost/mattermost-plugin-mscalendar/releases/latest)
+[![HW](https://img.shields.io/github/issues/mattermost/mattermost-plugin-mscalendar/Up%20For%20Grabs?color=dark%20green&label=Help%20Wanted)](/~https://github.com/mattermost/mattermost-plugin-mscalendar/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3A%22Up+For+Grabs%22+label%3A%22Help+Wanted%22)
 
 **Maintainer:** [@mickmister](/~https://github.com/mickmister)
 **Co-Maintainer:** [@larkox](/~https://github.com/larkox)