(dependabot): Bump MSTest.TestAdapter from 3.6.1 to 3.7.3

Bumps [MSTest.TestAdapter](https://github.com/microsoft/testfx) from 3.6.1 to 3.7.3.
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v3.6.1...v3.7.3)

---
updated-dependencies:
- dependency-name: MSTest.TestAdapter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

TJC.StringExtensions.Tests/TJC.StringExtensions.Tests.csproj

@@ -12,7 +12,7 @@
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="6.0.2" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="3.6.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="3.7.3" />
     <PackageReference Include="MSTest.TestFramework" Version="3.6.1" />
   </ItemGroup>