fix: add missing require

bethesque · bethesque · commit 0aa2d2a54b7b · 2018-07-24T14:58:07.000+10:00
diff --git a/lib/pact/retry.rb b/lib/pact/retry.rb
@@ -1,3 +1,5 @@
+require 'pact/errors'
+
 module Pact
   class Retry
     class RescuableError
