Add `cert` Property Request

[kchason]

Background Some Jira instances have been configured behind reverse proxies that require a client certificate for authentication to even hit the server. The requests library that is used by the connection library allows a cert property for this client authentication.

Change

• Add the keyword argument property (cert) to the AtlassianRestAPI class that is passed to an instance variable and passed to the session.request(...) function

References

• https://docs.python-requests.org/en/latest/user/advanced/#client-side-certificates

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (bb1c0f2) 34.46% compared to head (b6fd689) 34.47%.

:exclamation: Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1236 +/- ## ======================================= Coverage 34.46% 34.47% ======================================= Files 44 44 Lines 8097 8098 +1 Branches 1117 1117 ======================================= + Hits 2791 2792 +1 Misses 5192 5192 Partials 114 114 ``` | [Files Changed](https://app.codecov.io/gh/atlassian-api/atlassian-python-api/pull/1236?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [atlassian/rest\_client.py](https://app.codecov.io/gh/atlassian-api/atlassian-python-api/pull/1236?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-YXRsYXNzaWFuL3Jlc3RfY2xpZW50LnB5) | `67.97% <100.00%> (+0.18%)` | :arrow_up: |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.