Bump FluentAssertions and Microsoft.NETFramework.ReferenceAssemblies … #613

Job	Run time
Lint & Approval Tests	50s
Integrations Tests (3.12, ubuntu-latest)	2m 5s
Unit Tests (ubuntu-latest, net8.0)	42s
Integrations Tests (3.13, ubuntu-latest)	1m 59s
Integrations Tests (4.0, ubuntu-latest)	1m 57s
Unit Tests (windows-latest, net48)	1m 33s
Publish to NuGet	0s
	9m 6s

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