File icu4j-detectjava21.patch of Package icu4j

--- a/build.xml	2023-04-13 18:15:08.000000000 +0200
+++ b/build.xml	2023-09-21 08:36:23.783902985 +0200
@@ -134,6 +134,14 @@
         <matches string="${java.version}" pattern="^19((-.|\.\d).*)?"/>
     </condition>
 
+    <condition property="is.java20">
+        <matches string="${java.version}" pattern="^20((-.|\.\d).*)?"/>
+    </condition>
+
+    <condition property="is.java21">
+        <matches string="${java.version}" pattern="^21((-.|\.\d).*)?"/>
+    </condition>
+
   <condition property="is.java9.plus">
         <or>
             <isset property="is.java9"/>
@@ -147,6 +155,8 @@
             <isset property="is.java17"/>
             <isset property="is.java18"/>
             <isset property="is.java19"/>
+            <isset property="is.java20"/>
+            <isset property="is.java21"/>
         </or>
   </condition>