Add missing CST 210 (Crédito Presumido Operacional) to IBS/CBS enum

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rhfranzoni

NFe.Classes/Informacoes/Detalhe/Tributacao/Compartilhado/Tipos/IBSCBSTipos.cs

@@ -85,7 +85,14 @@ public enum CST
         [Description("Alíquota reduzida")]
         [XmlEnum("200")]
         Cst200,
-        
+
+        /// <summary>
+        ///     210 - Crédito Presumido Operacional
+        /// </summary>
+        [Description("Crédito Presumido Operacional")]
+        [XmlEnum("210")]
+        Cst210,
+
         /// <summary>
         ///     220 - Alíquota fixa
         /// </summary>