Kiwitcms-tap-plugin

- Update tcms-api to 8.6.0

- Update to
`tcms-api v8.3.0 <https://github.com/kiwitcms/tcms-api/#v830-10-april-2020>`_
which uses ``gssapi`` for Kerberos
- Requires MIT Kerberos for Windows if installed on Windows

This version works only with Kiwi TCMS v8.2 or later!

- Update to tcms-api==8.2.0
- Patch for changed return value in
``plugin_helpers.Backend.test_case_get_or_create()``
- Call ``plugin_helpers.backend.finish_test_run()`` when done. Fixes
`Issue 9 <https://github.com/kiwitcms/tap-plugin/issues/9>`_

This version works only with Kiwi TCMS v8.0 or later!

- Update to tcms-api==8.0.1
- Adjust plugin due to API changes in Kiwi TCMS v8.0
- Update ``tap.py`` from 2.6.2 to 3.0