Lock the JSON version until the root cause is found.

[tsogbadrakh-qp]

I have tested with 2.11...2.13, and all of them fail with the following error. Let's lock the version until we create a ticket and find the reason.

  test_0001_authorizes the transaction if accquire has authorizedERROR (0.00s)
Minitest::UnexpectedError:         NoMethodError: undefined method `call' for an instance of Hash
            /usr/local/bundle/gems/json-2.11.3/lib/json/common.rb:36:in `block in object_class_proc'
            /usr/local/bundle/gems/json-2.11.3/lib/json/common.rb:47:in `block in array_class_proc'
            /usr/local/bundle/gems/json-2.11.3/lib/json/common.rb:336:in `parse'
            /usr/local/bundle/gems/json-2.11.3/lib/json/common.rb:336:in `parse'
            /usr/local/bundle/gems/quickpay-ruby-client-3.0.2/lib/quickpay/api/client.rb:56:in `block (2 levels) in <class:Client>'

[tsogbadrakh-qp]

It's better to fix the issue related latest JSON