Update patch version for release - new version is 1.2.22-dev

Change-Id: If4430d49f9948e4482f13baf04e622eee59bf2c2
diff --git a/src/main/java/com/android/tools/r8/Version.java b/src/main/java/com/android/tools/r8/Version.java
index fb3b067..8a52881 100644
--- a/src/main/java/com/android/tools/r8/Version.java
+++ b/src/main/java/com/android/tools/r8/Version.java
@@ -11,7 +11,7 @@
 
   // 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 = "1.2.21-dev";
+  public static final String LABEL = "1.2.22-dev";
 
   private Version() {
   }