chore(deps): bump Discord.Net from 3.15.2 to 3.15.3

Bumps [Discord.Net](https://github.com/discord-net/Discord.Net) from 3.15.2 to 3.15.3.
- [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@3.15.2...3.15.3)

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

Signed-off-by: dependabot[bot] <[email protected]>

src/TiuSharpBot/TiuSharpBot.csproj

@@ -9,7 +9,7 @@
     <None Remove="Properties\**" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Discord.Net" Version="3.15.2" />
+    <PackageReference Include="Discord.Net" Version="3.15.3" />
     <PackageReference Include="F23.StringSimilarity" Version="6.0.0" />
     <PackageReference Include="Fergun.Interactive" Version="1.7.7" />
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="8.0.0" />