chore(deps): bump GraphQL.Server.Ui.Playground from 5.1.1 to 8.2.0

Bumps [GraphQL.Server.Ui.Playground](https://github.com/graphql-dotnet/server) from 5.1.1 to 8.2.0.
- [Release notes](https://github.com/graphql-dotnet/server/releases)
- [Commits](graphql-dotnet/server@5.1.1...8.2.0)

---
updated-dependencies:
- dependency-name: GraphQL.Server.Ui.Playground
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

NineChronicles.Headless/NineChronicles.Headless.csproj

@@ -32,7 +32,7 @@
     <PackageReference Include="GraphQL.Server.Transports.AspNetCore" Version="5.1.1" />
     <PackageReference Include="GraphQL.Server.Transports.AspNetCore.SystemTextJson" Version="5.1.1" />
     <PackageReference Include="GraphQL.Server.Transports.Subscriptions.WebSockets" Version="5.1.1" />
-    <PackageReference Include="GraphQL.Server.Ui.Playground" Version="5.1.1" />
+    <PackageReference Include="GraphQL.Server.Ui.Playground" Version="8.2.0" />
     <PackageReference Include="GraphQL.SystemTextJson" Version="4.7.1" />
     <PackageReference Include="Libplanet.Store.Remote" Version="$(LibplanetVersion)" />
     <PackageReference Include="MagicOnion" Version="6.1.3" />