Bump JSON Version, fixes #129

Explained [here](https://github.com/duckduckgo/p5-app-duckpan/issues/129#issuecomment-59374613) that JSON needs to be bumped to allow the PromptIfStale tests to pass.

- Could also add JSON::XS to the dist. There seems to be a discrepency between JSON < 2.9 and JSON::XS > 3 which was causing tests to fail.

cc// @mwmiller @jagtalon @tommytommytommy