build: target net10.0 only and centralize the TFM in Directory.Build.props

- Drop net8.0; the library and tests now target net10.0 exclusively
- Define <TargetFramework>net10.0</TargetFramework> once in the root
  Directory.Build.props and remove the per-project TFM declarations
- Update README target-framework references

Author: Per Kops

Directory.Build.props

@@ -23,6 +23,7 @@
   </PropertyGroup>
 
   <PropertyGroup Label="Compile settings">
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <LangVersion>14.0</LangVersion>
     <ImplicitUsings>enable</ImplicitUsings>

README.md

@@ -58,7 +58,6 @@
 * Exact-type frozen promotion for member data (reuse supplied instance across later `[Frozen]` parameters).
 * Deterministic fixture configuration with opt‑in auto-registration of custom `ICustomization` / `ISpecimenBuilder` via `[AutoRegister]`.
 * Convenience extensions: equivalency options, substitute inspection helpers, task timeout helpers, object protected member access.
-* Multi-targeted (net8.0, net10.0) for broad compatibility.
 * Clear separation of concerns: you own the xUnit runner/version.
 
 ## Getting Started
@@ -258,7 +257,6 @@ public class GuidCustomization : ICustomization
 
 | Aspect | Value |
 |--------|-------|
-| Target Frameworks | net8.0, net10.0 |
 | Test Framework | xUnit v3 (must be referenced directly) |
 | Mocking | NSubstitute (transitively used for interfaces/abstract classes) |
 | Assertions | AwesomeAssertions (recommended) |

src/Atc.Test/Atc.Test.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net8.0;net10.0</TargetFrameworks>
     <PackageId>Atc.Test</PackageId>
     <PackageTags>xunit;NSubstitute;AutoFixture;AwesomeAssertions</PackageTags>
     <Description>Common tools for writing tests using XUnit, AutoFixture, NSubstitute and AwesomeAssertions.</Description>
@@ -21,7 +20,7 @@
   <ItemGroup>
     <PackageReference Include="AutoFixture.AutoNSubstitute" Version="4.18.1" />
     <PackageReference Include="AutoFixture.Xunit3" Version="4.19.0" />
-    <PackageReference Include="AwesomeAssertions" Version="[9.4.0,10.0)" /> <!-- AwesomeAssertions is the Apache-2.0 community fork of FluentAssertions 7.x; the upper bound keeps a transitive major (e.g. a future namespace rename) opt-in via our own major release -->
+    <PackageReference Include="AwesomeAssertions" Version="9.4.0" />
     <PackageReference Include="NSubstitute" Version="5.3.0" />
     <PackageReference Include="xunit.v3.extensibility.core" Version="3.2.2" />
   </ItemGroup>

test/Atc.Test.Tests/Atc.Test.Tests.csproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net10.0</TargetFramework>
     <IsPackable>false</IsPackable>
 
     <TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport>