Update badge to use Actions (#80)

README.md

@@ -4,7 +4,7 @@ WiMigrator is a command line tool designed with the following goals in mind:
 * Real world example of how to use the WIT REST APIs
 * Cross platform support
 
-![Build Status](https://dev.azure.com/vsts-wit/_apis/public/build/definitions/2a08f204-c80c-4f7e-82c8-f27e28f2becd/1/badge)
+![Build Status](https://github.com/microsoft/vsts-work-item-migrator/workflows/Build/badge.svg)
 
 # Features
 * Migrate the latest revision of a work item or set of work items based on the provided query, including: