Set default version

Jellyfin.Server/Extensions/ApiServiceCollectionExtensions.cs

@@ -260,7 +260,7 @@ namespace Jellyfin.Server.Extensions
         {
             return serviceCollection.AddSwaggerGen(c =>
             {
-                var version = typeof(ApplicationHost).Assembly.GetName().Version?.ToString();
+                var version = typeof(ApplicationHost).Assembly.GetName().Version?.ToString() ?? "0.0.0.1";
                 c.SwaggerDoc("api-docs", new OpenApiInfo
                 {
                     Title = "Jellyfin API",