Bump Microsoft.TestPlatform.ObjectModel from 17.3.0 to 17.3.1 (#166)

Author: dependabot[bot]

source/TestAdapter/nanoFramework.TestAdapter.csproj

@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="ICSharpCode.Decompiler" Version="7.2.1.6856" />
-    <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Version="17.3.0" />
+    <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Version="17.3.1" />
     <PackageReference Include="nanoFramework.nanoCLR.Win32" GeneratePathProperty="true">
       <Version>1.8.0.440</Version>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>