Update echo dotnet version

2022-10-11 15:39:48 +01:00 · 2022-10-11 15:39:48 +01:00 · 9178c57610
--- a/Echo/Echo/Echo.csproj
+++ b/Echo/Echo/Echo.csproj
@ -2,7 +2,7 @@

  <PropertyGroup>
    <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
    <Platforms>x64</Platforms>
  </PropertyGroup>