[Feature] Add Role & Attachment flags (#2720)

* initial commit

* oops

* another typo -_-

* Update AttachmentFlags.cs

Made this on my phone lol

* Update AttachmentFlags.cs

* -line

src/Discord.Net.WebSocket/Entities/Roles/SocketRole.cs

@@ -44,6 +44,9 @@ namespace Discord.WebSocket
         /// <inheritdoc />
         public RoleTags Tags { get; private set; }
 
+        /// <inheritdoc />
+        public RoleFlags Flags { get; private set; }
+
         /// <inheritdoc />
         public DateTimeOffset CreatedAt => SnowflakeUtils.FromSnowflake(Id);
         /// <summary>
@@ -82,6 +85,8 @@ namespace Discord.WebSocket
             Position = model.Position;
             Color = new Color(model.Color);
             Permissions = new GuildPermissions(model.Permissions);
+            Flags = model.Flags;
+
             if (model.Tags.IsSpecified)
                 Tags = model.Tags.Value.ToEntity();