chore(deps): update dependency tunit to 1.21.0

Author: renovate[bot]

test/Streamlabs.SocketClient.Tests/Streamlabs.SocketClient.Tests.csproj

@@ -13,7 +13,7 @@
     <PackageReference Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.5.2" />
     <PackageReference Include="Microsoft.Testing.Extensions.TrxReport" Version="2.1.0" />
     <PackageReference Include="NSubstitute" Version="5.3.0" />
-    <PackageReference Include="TUnit" Version="1.19.22" />
+    <PackageReference Include="TUnit" Version="1.21.0" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Streamlabs.SocketClient\Streamlabs.SocketClient.csproj" />