Show the build status badges of master branch

Author: ringods

README.md

@@ -7,9 +7,9 @@ Terraform Provider for Gitlab
 - [![Gitter chat](https://badges.gitter.im/hashicorp-terraform/Lobby.png)](https://gitter.im/hashicorp-terraform/Lobby)
 - Mailing list: [Google Groups](http://groups.google.com/group/terraform-tool)
 - Build status:
-  - ![Unit Tests](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Unit%20Tests/badge.svg)
-  - ![Acceptance Tests](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Acceptance%20Tests/badge.svg)
-  - ![Website Build](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Website%20Build/badge.svg)
+  - ![Unit Tests](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Unit%20Tests/badge.svg?branch=master)
+  - ![Acceptance Tests](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Acceptance%20Tests/badge.svg?branch=master)
+  - ![Website Build](https://github.com/terraform-providers/terraform-provider-gitlab/workflows/Website%20Build/badge.svg?branch=master)
 
 Requirements
 ------------