Bump test project nuget references

Author: SeanFeldman

test/Microsoft.Azure.ServiceBus.UnitTests/Microsoft.Azure.ServiceBus.UnitTests.csproj

@@ -36,14 +36,14 @@
     <compile Remove="..\..\test\Microsoft.Azure.ServiceBus.UnitTests\Diagnostics\SubscriptionClientDiagnosticsTests.cs" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.6.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
     <PackageReference Include="System.Net.WebSockets.Client" Version="4.3.2" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
-    <PackageReference Include="xunit" Version="2.3.1" />
-    <PackageReference Include="PublicApiGenerator" Version="6.5.0" />
-    <PackageReference Include="ApprovalTests" Version="3.0.13" NoWarn="NU1701" />
-    <PackageReference Include="ApprovalUtilities" Version="3.0.13" NoWarn="NU1701" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="PublicApiGenerator" Version="8.0.1" />
+    <PackageReference Include="ApprovalTests" Version="3.0.18" NoWarn="NU1701" />
+    <PackageReference Include="ApprovalUtilities" Version="3.0.18" NoWarn="NU1701" />
     <PackageReference Include="Microsoft.Extensions.PlatformAbstractions" Version="1.1.0" />
   </ItemGroup>