Fix status badge (#15)

README.md

@@ -1,5 +1,5 @@
 # Microsoft.MSBuildCache
-[![Build Status](https://dev.azure.com/msbuildcache/public/_apis/build/status%2FMicrosoft.MSBuildCache?repoName=microsoft%2FMSBuildCache&branchName=refs%2Fpull%2F1%2Fmerge)](https://dev.azure.com/msbuildcache/public/_build/latest?definitionId=1&repoName=microsoft%2FMSBuildCache&branchName=refs%2Fpull%2F1%2Fmerge)
+[![Build Status](https://dev.azure.com/msbuildcache/public/_apis/build/status%2FMicrosoft.MSBuildCache?repoName=microsoft%2FMSBuildCache&branchName=main)](https://dev.azure.com/msbuildcache/public/_build/latest?definitionId=1&repoName=microsoft%2FMSBuildCache&branchName=main)
 
 This project provides plugin implementations for the experimental [MSBuild Project Cache](https://github.com/dotnet/msbuild/blob/main/documentation/specs/project-cache.md), which enables project-level caching within MSBuild.
 
@@ -154,4 +154,4 @@ This project may contain trademarks or logos for projects, products, or services
 trademarks or logos is subject to and must follow 
 [Microsoft's Trademark & Brand Guidelines](https://www.microsoft.com/en-us/legal/intellectualproperty/trademarks/usage/general).
 Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.
-Any use of third-party trademarks or logos are subject to those third-party's policies.
+Any use of third-party trademarks or logos are subject to those third-party's policies.