Use netcoreapp3.1 instead of netcoreapp3.0

[konard]

Numbers/csharp/Platform.Numbers.Benchmarks/Platform.Numbers.Benchmarks.csproj

Line 5 in 8661bfc

<TargetFramework>netcoreapp3.0</TargetFramework>

[konard]

Current Status Analysis

I've reviewed the current state of the repository and found that:

Original Issue: Change from netcoreapp3.0 to netcoreapp3.1
Current State: All projects now use net8 target framework

Files mentioned in the issue:

• csharp/Platform.Numbers.Benchmarks/Platform.Numbers.Benchmarks.csproj - now uses net8
• csharp/Platform.Numbers.Tests/Platform.Numbers.Tests.csproj - now uses net8
• csharp/Platform.Numbers/Platform.Numbers.csproj - now uses net8

Question:

Since the repository has already been upgraded to net8 (which is much newer than netcoreapp3.1), should this issue be:

1. Closed as resolved - The intent (using a newer framework) has been achieved
2. Kept open with modified scope - If there's a specific need to support multiple target frameworks including netcoreapp3.1

Please clarify the preferred approach so I can implement the appropriate solution.