Update patch version for release

New version is v1.2.8-dev

R=ager

Change-Id: I689a33fdb8506c400e3c399f0f5e6e5bb86abab4
diff --git a/src/main/java/com/android/tools/r8/Version.java b/src/main/java/com/android/tools/r8/Version.java
index eb6718d..3639d9e 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 = "v1.2.7-dev";
+  public static final String LABEL = "v1.2.8-dev";
 
   private Version() {
   }