Add emulator handler for RateLimitByKey - #221

Non-nullable property 'Algorithm' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Id' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Dereference of a possibly null reference.

Possible null reference argument for parameter 'parameters' in 'bool CompilerUtils.AddAttribute(XElement element, IReadOnlyDictionary<string, InitializerValue> parameters, string key, string attName)'.

Possible null reference argument for parameter 'node' in 'void IReturnValueMethodPolicyHandler.Handle(IDocumentCompilationContext context, InvocationExpressionSyntax node, string variableName)'.

Possible null reference argument for parameter 'key' in 'bool IReadOnlyDictionary<string, IReturnValueMethodPolicyHandler>.TryGetValue(string key, out IReturnValueMethodPolicyHandler value)'.

- Add a dependency group for net8.0 to the nuspec

Some target frameworks declared in the dependencies group of the nuspec and the lib/ref folder do not have exact matches in the other location. Consult the list of actions below:

This compiler extension should not be implemented in an assembly with target framework '.NET 8.0'. References to other target frameworks will cause the compiler to behave unpredictably. (https://github.com/dotnet/roslyn-analyzers/blob/main/docs/rules/RS1041.md)