[PersistentStorage.FileSystem] Replace .NET 6 target with .NET 8 for test project (open-telemetry#2163)

Author: joegoldman2

src/OpenTelemetry.PersistentStorage.FileSystem/OpenTelemetry.PersistentStorage.FileSystem.csproj

@@ -2,17 +2,14 @@
 
   <PropertyGroup>
     <!-- OmniSharp/VS Code requires TargetFrameworks to be in descending order for IntelliSense and analysis. -->
-    <TargetFrameworks>netstandard2.0</TargetFrameworks>
-    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net462</TargetFrameworks>
+    <TargetFrameworks>$(NetStandardMinimumSupportedVersion)</TargetFrameworks>
+    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);$(NetFrameworkMinimumSupportedVersion)</TargetFrameworks>
     <Description>OpenTelemetry Persistent Storage</Description>
+    <NoWarn>$(NoWarn);1591</NoWarn>
     <MinVerTagPrefix>PersistentStorage-</MinVerTagPrefix>
     <PackageValidationBaselineVersion>1.0.0</PackageValidationBaselineVersion>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <NoWarn>$(NoWarn),1591</NoWarn>
-  </PropertyGroup>
-
   <ItemGroup>
     <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.PersistentStorage.Abstractions\OpenTelemetry.PersistentStorage.Abstractions.csproj" />
   </ItemGroup>

test/OpenTelemetry.PersistentStorage.FileSystem.Tests/OpenTelemetry.PersistentStorage.FileSystem.Tests.csproj

@@ -2,8 +2,8 @@
 
   <PropertyGroup>
     <!-- OmniSharp/VS Code requires TargetFrameworks to be in descending order for IntelliSense and analysis. -->
-    <TargetFrameworks>$(SupportedNetTargets)</TargetFrameworks>
-    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net462</TargetFrameworks>
+    <TargetFrameworks>$(SupportedNetTargetsWithoutNet6)</TargetFrameworks>
+    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);$(NetFrameworkMinimumSupportedVersion)</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>