Update ICU to 58.1

source/i18n/unicode/upluralrules.h

Index: source/i18n/unicode/upluralrules.h
diff --git a/source/i18n/unicode/upluralrules.h b/source/i18n/unicode/upluralrules.h
index 5bcadd4bda60f41c74a0f45ebe115e07a4b247d3..52e34d8d25dd664eb6e9abd94e173129bc0ba134 100644
--- a/source/i18n/unicode/upluralrules.h
+++ b/source/i18n/unicode/upluralrules.h
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 *****************************************************************************************
 * Copyright (C) 2010-2013, International Business Machines
@@ -52,11 +54,13 @@ enum UPluralType {
      * @stable ICU 50
      */
     UPLURAL_TYPE_ORDINAL,
+#ifndef U_HIDE_DEPRECATED_API
     /**
-     * Number of Plural rules types.
-     * @stable ICU 50
+     * One more than the highest normal UPluralType value.
+     * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
      */
     UPLURAL_TYPE_COUNT
+#endif  // U_HIDE_DEPRECATED_API
 };
 /**
  * @stable ICU 50