corrected our readme to accurate describe the .NET versions we support (replaced Core 2.0+ with Core 3.1+) (#3039)

updated the Stripe.net.csproj project description to match

Author: jar-stripe

README.md

@@ -4,7 +4,7 @@
 [![Build Status](https://github.com/stripe/stripe-dotnet/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/stripe/stripe-dotnet/actions?query=branch%3Amaster)
 [![Coverage Status](https://coveralls.io/repos/github/stripe/stripe-dotnet/badge.svg?branch=master)](https://coveralls.io/github/stripe/stripe-dotnet?branch=master)
 
-The official [Stripe][stripe] .NET library, supporting .NET Standard 2.0+, .NET Core 2.0+, and .NET Framework 4.6.1+.
+The official [Stripe][stripe] .NET library, supporting .NET Standard 2.0+, .NET Core 3.1+, and .NET Framework 4.6.1+.
 
 ## Installation
 

src/Stripe.net/Stripe.net.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <Description>Stripe.net is a sync/async .NET 4.6.1+ client, and a portable class library for the Stripe API.  (Official Library)</Description>
+    <Description>Stripe.net is a sync/async client and portable class library for the Stripe API, supporting .NET Standard 2.0+, .NET Core 3.1+, and .NET Framework 4.6.1+. (Official Library)</Description>
     <Version>47.2.0</Version>
     <LangVersion>8</LangVersion>
     <Authors>Stripe, Jayme Davis</Authors>