trying to add compatible DiagnosticSource version for framework

Author: chojomok

tracer/test/test-applications/integrations/Samples.Quartz/Samples.Quartz.csproj

@@ -9,11 +9,16 @@
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateTargetFrameworkAttribute>false</GenerateTargetFrameworkAttribute>
+    <!-- Multi-target to support both .NET Framework and .NET Core scenarios -->
+    <TargetFrameworks Condition="'$(OS)' == 'Windows_NT'">net48;netcoreapp3.0;netcoreapp3.1;net5.0;net6.0;net7.0;net8.0;net9.0;net10.0</TargetFrameworks>
+    <TargetFrameworks Condition="'$(OS)' != 'Windows_NT'">netcoreapp3.0;netcoreapp3.1;net5.0;net6.0;net7.0;net8.0;net9.0;net10.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Quartz" Version="$(ApiVersion)" />
-    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="8.0.0" />
+    <!-- Use older DiagnosticSource for .NET Framework and .NET Core 3.x to match what's available in the runtime -->
+    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="4.4.1" Condition="'$(TargetFramework)' == 'net48' OR '$(TargetFramework)' == 'netcoreapp3.0' OR '$(TargetFramework)' == 'netcoreapp3.1'" />
+    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="8.0.0" Condition="'$(TargetFramework)' != 'net48' AND '$(TargetFramework)' != 'netcoreapp3.0' AND '$(TargetFramework)' != 'netcoreapp3.1'" />
     <!-- Uncomment the packages below to use OTEL instrumentation -->
     <!-- <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.12.0" /> -->
     <!-- <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.12.0" /> -->