Same version of NUnit3TestAdapter accross all test projects

Author: alex-kulakov

Orm/Xtensive.Orm.Manual/Xtensive.Orm.Manual.csproj

@@ -27,7 +27,7 @@
     <!-- <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0" /> -->
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.2" />
     <PackageReference Include="NUnit" Version="3.12.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="3.15.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
   </ItemGroup>
   <ItemGroup>
     <Content Include="EntitySets\DatabaseSchema.gif" />