Rename ErbTracker -> ERBTracker

Author: dasch

lib/cache_digests/dependency_tracker.rb

@@ -22,7 +22,7 @@ def self.unregister_tracker(handler)
       @trackers.delete(handler)
     end
 
-    class ErbTracker
+    class ERBTracker
       EXPLICIT_DEPENDENCY = /# Template Dependency: (\S+)/
 
       # Matches:
@@ -85,6 +85,6 @@ def explicit_dependencies
         end
     end
 
-    register_tracker(:erb, ErbTracker)
+    register_tracker(:erb, ERBTracker)
   end
 end