Mark InvokeRecAction as obsolete with guidance

Added the `[Obsolete]` attribute to the `InvokeRecAction` method
in the `ReC.Client` namespace to discourage its use. The attribute
recommends using the `InvokeRecActionAsync` method instead to
avoid potential deadlocks and improve performance.

src/ReC.Client/ReCClient.cs

@@ -36,6 +36,7 @@ namespace ReC.Client
         /// </summary>
         /// <param name="profileId"></param>
         /// <returns>True if the request was successful, false otherwise</returns>
+        [Obsolete("Use InvokeRecActionAsync instead to avoid potential deadlocks and improve performance.")]
         public bool InvokeRecAction(int profileId)
         {
             var resp = _http.PostAsync($"api/RecAction/invoke/{profileId}", content: null).GetAwaiter().GetResult();