Log Message:
Update ruby-mocha to to 0.13.3.

# Release Notes

## 0.13.3

* Allow `Mocha::ParameterMatchers#includes` to accept multiple items. Thanks
  to @simao.
* Allow stubbing of *private* `Kernel` methods. Fixes #134. Thanks to @camski
  for reporting.
* Avoid a warning when `test/unit/version` is required by other libraries in
  the same project. Fixes #140. Thanks to @tmiller.
* Make auto-activation of Test::Unit integration more resilient. This change
  is specifically to cope with the nasty re-defining of classes that is done
  by the `minitest-spec-rails` gem. Fixes #143. Thanks to @tubaxenor for
  reporting.
* Safer restoration of stubbed method visibility. Fixes #141. Thanks to @tmm1.
* Ensure `Mockery` instance gets reset even if exception raised. Fixes #144.
* Adapt Mocha acceptance tests to cope with changes in output from latest
  (v4.6.2) of MiniTest.
* Updates to README about Rails compatibility.