Update patch version for release

New version is v1.2.6-dev

Change-Id: Ie908a7518058daef5ec0bedbaa4d6ce22ac11778
diff --git a/src/main/java/com/android/tools/r8/Version.java b/src/main/java/com/android/tools/r8/Version.java
index 6076345..5a0d2c4 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 = "v1.2.5-dev";
+  public static final String LABEL = "v1.2.6-dev";
 
   private Version() {
   }