Version 8.4.21

Promote version 8.4.21-dev to 8.4.21.

Release branch for Android Studio 2023.3.1 (Jellyfish) / AGP 8.4.

Change-Id: Ic2052dbca0ab042356cee83810754ac6626ed85c
diff --git a/src/main/java/com/android/tools/r8/Version.java b/src/main/java/com/android/tools/r8/Version.java
index d3ca249..e542e14 100644
--- a/src/main/java/com/android/tools/r8/Version.java
+++ b/src/main/java/com/android/tools/r8/Version.java
@@ -13,7 +13,7 @@
 
   // This field is accessed from release scripts using simple pattern matching.
   // Therefore, changing this field could break our release scripts.
-  public static final String LABEL = "8.4.21-dev";
+  public static final String LABEL = "8.4.21";
 
   private Version() {
   }