Update patch version for release - new version is 1.5.5-dev

Change-Id: I78c6d3990d6821cbfbc4b75d13265216cd01cb53
diff --git a/src/main/java/com/android/tools/r8/Version.java b/src/main/java/com/android/tools/r8/Version.java
index 010a851..95bfbc0 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 = "1.5.4-dev";
+  public static final String LABEL = "1.5.5-dev";
 
   private Version() {
   }