Target the latest version of fluent and the latest TFM to unblock CI tests.

test/dotnet-core-uninstall.Tests/dotnet-core-uninstall.Tests.csproj

@@ -1,10 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="FluentAssertions" Version="5.6.0" />
+    <PackageReference Include="FluentAssertions" Version="6.7.0" />
   </ItemGroup>
 
   <ItemGroup>