2.0.0 - Tasks under the hood

• F# 6 task{} instead of async{} under the hood - #200
• BREAKING: ProvidedApiClientBase.CallAsync returns task instead of async
• BREAKING: task CE wrap all exceptions in AggregateException (with OpenApiException inside)
• Model enums as string, int32 or boolean (Fixed #186 )
• Add Accept header to all requests (Fixed #196)
• Supported requests with octet-stream body content #203
• Added missing properties to OpenApiException #222
• Changed raise to calling Reraise() extension method to preserve the call stack #230
• Microsoft.OpenApi (1.6.10)
• FSharp.SystemTextJson (1.2.42)
• Removed the System.Net.Http dependency (#221)
• fix: accept "default" as "ok response" fallback (#223)
• Minor performance tweaks (#233)