Pack update to 0.6.0

[nzlosh]

This pull requests supersedes #11

• Use patched icinga2api for Python3 support because upstream is unresponsive. nzlosh/python-icinga2api@f59d6cd
• Generate documentation with pack2md
• Format code using Black
• Service field is now optional (returns "n/a" when statechange event doesn't have a service field)
• Timestamp field is now sent in the StackStorm trigger to allow for detection of lag in events.
• Version bump to 0.6.0 along with changelog update.

[blag]

Awesome, thanks!

Can you add build_and_test_python36 to the requires list here:

workflows:
  version: 2
  # Workflow which runs on each push
  build_test_deploy_on_push:
    jobs:
      - build_and_test_python27
      - build_and_test_python36
      - deploy:
          requires:
            - build_and_test_python27
            - build_and_test_python36  # <--
          filters:
            branches:
              only: master

That will ensure that the pack is only ever deployed if both the Python 2 and 3 tests pass.

[nzlosh]

@blag ☝️ Python36 added as requested.

[blag]

Thanks!