Bump the mstest group with 2 updates

Bumps the mstest group with 2 updates: [MSTest.TestAdapter](https://github.com/microsoft/testfx) and [MSTest.TestFramework](https://github.com/microsoft/testfx).


Updates `MSTest.TestAdapter` from 2.2.10 to 3.1.1
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v2.2.10...v3.1.1)

Updates `MSTest.TestFramework` from 2.2.10 to 3.1.1
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v2.2.10...v3.1.1)

---
updated-dependencies:
- dependency-name: MSTest.TestAdapter
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: mstest
- dependency-name: MSTest.TestFramework
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: mstest
...

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

Tests/UWP.Specs/UWP.Specs.csproj

@@ -1,4 +1,4 @@
-<Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -86,10 +86,10 @@
       <Version>6.2.14</Version>
     </PackageReference>
     <PackageReference Include="MSTest.TestAdapter">
-      <Version>2.2.10</Version>
+      <Version>3.1.1</Version>
     </PackageReference>
     <PackageReference Include="MSTest.TestFramework">
-      <Version>2.2.10</Version>
+      <Version>3.1.1</Version>
     </PackageReference>
     <PackageReference Include="System.Xml.XPath.XmlDocument">
       <Version>4.3.0</Version>