Bump xunit.runner.msbuild from 2.7.0 to 2.8.0 (#268)

Bumps [xunit.runner.msbuild](https://github.com/xunit/xunit) from 2.7.0 to 2.8.0.
- [Commits](xunit/xunit@2.7.0...2.8.0)

---
updated-dependencies:
- dependency-name: xunit.runner.msbuild
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Diff for: src/Directory.Build.targets

@@ -13,7 +13,7 @@
 	<ItemGroup Condition="'$(IncludeTesting)' == 'true'">
 		<PackageReference Include="xunit" Version="2.7.0" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="2.8.0" />
-		<PackageReference Include="xunit.runner.msbuild" Version="2.7.0" />
+		<PackageReference Include="xunit.runner.msbuild" Version="2.8.0" />
 		<PackageReference Include="Moq" Version="4.18.4" />
 		<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
 	</ItemGroup>