Pass branch name to AppVeyor badge
Without this, we were getting the status for the most recent run,
which could include a broken run from a topic branch someone was using
for a PR.
@@ -9,7 +9,7 @@ If you are learning about Pulumi for the first time, please [visit our docs webs
| Architecture | Build Status |
| ------------ | ------------ |
| Linux x64 | [![Linux x64 Build Status](https://travis-ci.com/pulumi/pulumi.svg?token=cTUUEgrxaTEGyecqJpDn&branch=master)](https://travis-ci.com/pulumi/pulumi) |
-| Windows x64 | [![Windows x64 Build Status](https://ci.appveyor.com/api/projects/status/uqrduw6qnoss7g4i?svg=true)](https://ci.appveyor.com/project/pulumi/pulumi) |
+| Windows x64 | [![Windows x64 Build Status](https://ci.appveyor.com/api/projects/status/uqrduw6qnoss7g4i?svg=true&branch=master)](https://ci.appveyor.com/project/pulumi/pulumi) |
## Installing
