Update dependency FluentAssertions to v8

Author: renovate[bot]

tests/TurnerSoftware.Aqueduct.Tests/TurnerSoftware.Aqueduct.Tests.csproj

@@ -9,7 +9,7 @@
 	</PropertyGroup>
 
 	<ItemGroup>
-		<PackageReference Include="FluentAssertions" Version="7.1.0" />
+		<PackageReference Include="FluentAssertions" Version="8.1.0" />
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
 		<PackageReference Include="MSTest.TestAdapter" Version="3.7.3" />
 		<PackageReference Include="MSTest.TestFramework" Version="3.7.3" />