Bump version 0.15.6

Trim · Trim · commit 3e6314d0421e · 2019-02-25T09:26:38.000+01:00
diff --git a/lib/html/pipeline/version.rb b/lib/html/pipeline/version.rb
@@ -1,5 +1,5 @@
 module HTML
   class Pipeline
-    VERSION = "0.15.5"
+    VERSION = "0.15.6"
   end
 end
