Make systemprompt.txt copy with build

Author: jeppevinkel

AiHelpBot/AiHelpBot.csproj

@@ -14,8 +14,10 @@
     </ItemGroup>
 
     <ItemGroup>
-      <PackageReference Include="Discord.Net" Version="3.16.0" />
-      <PackageReference Include="OpenAI" Version="2.0.0-beta.12" />
+    <ItemGroup>
+      <None Update="SystemPrompt.txt">
+        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      </None>
     </ItemGroup>
 
 </Project>