chore: update simple example

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Author: appleboy

_example/simple/go.mod

@@ -2,4 +2,4 @@ module example
 
 go 1.16
 
-require github.com/appleboy/queue v0.0.4-0.20210727142412-eaaf46bd6231
+require github.com/appleboy/queue v0.0.4-0.20210728132114-6b35f5805523

_example/simple/go.sum

@@ -2,6 +2,8 @@ github.com/appleboy/queue v0.0.4-0.20210726090849-82cf3ebeafc5 h1:UE6zMJQObLz/E/
 github.com/appleboy/queue v0.0.4-0.20210726090849-82cf3ebeafc5/go.mod h1:cEQW2y7dduAUqUGnGJEK9oM5bZLlc0+3HI9bTUL0+Ek=
 github.com/appleboy/queue v0.0.4-0.20210727142412-eaaf46bd6231 h1:OGNVcnnlPLRiK27xIcinWDCITRNJYHdO5SBLfl2DuFA=
 github.com/appleboy/queue v0.0.4-0.20210727142412-eaaf46bd6231/go.mod h1:cEQW2y7dduAUqUGnGJEK9oM5bZLlc0+3HI9bTUL0+Ek=
+github.com/appleboy/queue v0.0.4-0.20210728132114-6b35f5805523 h1:+SPSATrAMClbv8JMv1G8wsmq+cIs/nS9bLLWgqcyX8E=
+github.com/appleboy/queue v0.0.4-0.20210728132114-6b35f5805523/go.mod h1:cEQW2y7dduAUqUGnGJEK9oM5bZLlc0+3HI9bTUL0+Ek=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8=