Bump MSTest from 3.2.2 to 3.3.1 (#122)

Author: dependabot[bot]

src/Sep.Test/Sep.Test.csproj

@@ -20,7 +20,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="PublicApiGenerator" Version="11.1.0" />
-    <PackageReference Include="MSTest" Version="3.2.2" />
+    <PackageReference Include="MSTest" Version="3.3.1" />
   </ItemGroup>
 
 </Project>