Bump Microsoft.Build from 18.6.3 to 18.7.1

---
updated-dependencies:
- dependency-name: Microsoft.Build
  dependency-version: 18.7.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -4,7 +4,7 @@
     <CentralPackageTransitivePinningEnabled>false</CentralPackageTransitivePinningEnabled>
   </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="Microsoft.Build" Version="18.6.3" />
+    <PackageVersion Include="Microsoft.Build" Version="18.7.1" />
     <PackageVersion Include="Microsoft.Build.Locator" Version="1.11.2" />
     <PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="10.0.300" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />