Update GitHub workflow badge in README.md

Author: joschi

README.md

@@ -2,7 +2,7 @@
 
 Compare two OpenAPI specifications (3.x) and render the difference to HTML plaintext, or Markdown files.
 
-[![Test](https://github.com/OpenAPITools/openapi-diff/workflows/Test/badge.svg)](https://github.com/OpenAPITools/openapi-diff/actions?query=branch%3Amaster+workflow%3ATest+)
+[![Build](https://github.com/OpenAPITools/openapi-diff/workflows/Main%20Build/badge.svg)](https://github.com/OpenAPITools/openapi-diff/actions?query=branch%3Amaster+workflow%3A"Main+Build")
 
 [![Join the Slack chat room](https://img.shields.io/badge/Slack-Join%20the%20chat%20room-orange)](https://join.slack.com/t/openapi-generator/shared_invite/enQtNzAyNDMyOTU0OTE1LTY5ZDBiNDI5NzI5ZjQ1Y2E5OWVjMjZkYzY1ZGM2MWQ4YWFjMzcyNDY5MGI4NjQxNDBiMTlmZTc5NjY2ZTQ5MGM)