test: remove net5.0 target

Author: phnx47

tests/Prometheus.Client.DependencyInjection.Tests.csproj

@@ -1,8 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <!-- netcoreapp2.1 => netstandard2.0 -->
-    <!-- netcoreapp3.1;net5.0 => netstandard2.1 -->
-    <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net5.0;net6.0;net7.0</TargetFrameworks>
+    <!-- netcoreapp3.1 => netstandard2.1 -->
+    <TargetFrameworks>netcoreapp2.1;netcoreapp3.1;net6.0;net7.0</TargetFrameworks>
     <IsPackable>false</IsPackable>
     <InvariantGlobalization>true</InvariantGlobalization>
     <NoWarn>$(NoWarn);CS0618</NoWarn>
@@ -32,6 +32,11 @@
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' != 'netcoreapp2.1'">
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.1" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'net6.0' OR '$(TargetFramework)' == 'net7.0'">
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1'">