Update demo sdk to .net 6.0

Author: myloveCc

example/NETCore.Encrypt.Demo/NETCore.Encrypt.Demo.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

example/NETCore.Encrypt.Demo/Program.cs

@@ -110,7 +110,7 @@ static void Main(string[] args)
 
             Console.WriteLine($"Test str:{testStr}");
 
-            var saveDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory.Split("NETCore.Encrypt.Demo")[0], "Framework472.EncryptDemo\\bin\\Debug");
+            var saveDir = AppDomain.CurrentDomain.BaseDirectory;
 
             //save public key
             var publicKeySavePath = Path.Combine(saveDir, "privateKey.txt");