Add enum and date for 18.0 (#1212)

* Add enum and date for 18.0

* Guess a different date

Author: nedley

unicodetools/data/emoji/dev/internal/emoji-ordering-rules.txt

@@ -1,4 +1,4 @@
-<!-- Machine-readable version of the emoji ordering rules for v17.0 (corresponding to CLDR). -->
+<!-- Machine-readable version of the emoji ordering rules for v18.0 (corresponding to CLDR). -->
 <collation type='emoji'>
 <cr><![CDATA[
 # START AUTOGENERATED EMOJI ORDER

unicodetools/src/main/java/org/unicode/tools/emoji/Emoji.java

@@ -83,6 +83,7 @@ public class Emoji {
     // situation)
 
     // Constants for versions
+    public static final VersionInfo VERSION18 = VersionInfo.getInstance(18);
     public static final VersionInfo VERSION17 = VersionInfo.getInstance(17);
     public static final VersionInfo VERSION16 = VersionInfo.getInstance(16);
     public static final VersionInfo VERSION15_1 = VersionInfo.getInstance(15, 1);
@@ -136,6 +137,7 @@ public class Emoji {
 
     public static final Map<VersionInfo, String> EMOJI_TO_DATE =
             ImmutableMap.<VersionInfo, String>builder()
+                    .put(VERSION18, "2026-09-15")
                     .put(VERSION17, "2025-09-09")
                     .put(VERSION16, "2024-09-10")
                     .put(VERSION15_1, "2023-09-12")