Bump Discord.Net from 2.4.0 to 3.12.0

Bumps [Discord.Net](https://github.com/discord-net/Discord.Net) from 2.4.0 to 3.12.0.
- [Release notes](https://github.com/discord-net/Discord.Net/releases)
- [Changelog](https://github.com/discord-net/Discord.Net/blob/dev/CHANGELOG.md)
- [Commits](discord-net/Discord.Net@2.4.0...3.12.0)

---
updated-dependencies:
- dependency-name: Discord.Net
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/Sergen.Core/Sergen.Core.csproj

@@ -10,7 +10,7 @@
     <PackageReference Include="Microsoft.Extensions.Options" Version="6.0.0" />
     <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.16.1" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
-    <PackageReference Include="Discord.Net" Version="2.4.0" />
+    <PackageReference Include="Discord.Net" Version="3.12.0" />
     <PackageReference Include="Docker.DotNet" Version="3.125.15" />
   </ItemGroup>
   <ItemGroup>

src/Sergen.Main/Sergen.Main.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
@@ -16,7 +16,7 @@
     </Content>
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Discord.Net" Version="2.4.0" />
+    <PackageReference Include="Discord.Net" Version="3.12.0" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Sergen.Core\Sergen.Core.csproj" />