fix issue events schema

[daigotanaka]

Description of change

Some of the properties were marked as "null" type.
Change them to nullable string type.

Manual QA steps

Before the fix, the tap was throwing an exception with the null type issue.
After the fix, the tap correctly fetches the data and stdout.

Risks

• None since the scope is limited to the previously broken issue_events stream.

Rollback steps

• revert this branch

[cmerrick]

Hi @daigotanaka, thanks for your contribution!

In order for us to evaluate and accept your PR, we ask that you sign a contribution license agreement. It's all electronic and will take just minutes.

[daigotanaka]

@cmerrick: Done signing the agreement.

[cmerrick]

You did it @daigotanaka!

Thank you for signing the Singer Contribution License Agreement.

[daigotanaka]

Just realized this could be a duplicated effort with #97 to solve #95, except that I corrected other fields on top of description.

[luandy64]

@daigotanaka this looks good to me. I want to run some tests tomorrow, and then I can merge

[luandy64]

I think this is wrong.

I made an issue on this repo (#104) and the milestone there returned as an object:

'milestone': {'title': 'new-feature'}

[luandy64]

Oh, I was looking at the wrong milestone, but it's still an object:

           'milestone': {'closed_at': None,
                         'closed_issues': 0,
                         'created_at': '2021-02-05T15:49:29Z',
                         'creator': {'avatar_url': 'https://avatars.githubusercontent.com/u/19473996?v=4',
                                     'events_url': 'https://api.github.com/users/luandy64/events{/privacy}',
                                     'followers_url': 'https://api.github.com/users/luandy64/followers',
                                     'following_url': 'https://api.github.com/users/luandy64/following{/other_user}',
                                     'gists_url': 'https://api.github.com/users/luandy64/gists{/gist_id}',
                                     'gravatar_id': '',
                                     'html_url': 'https://github.com/luandy64',
                                     'id': 19473996,
                                     'login': 'luandy64',
                                     'node_id': 'MDQ6VXNlcjE5NDczOTk2',
                                     'organizations_url': 'https://api.github.com/users/luandy64/orgs',
                                     'received_events_url': 'https://api.github.com/users/luandy64/received_events',
                                     'repos_url': 'https://api.github.com/users/luandy64/repos',
                                     'site_admin': False,
                                     'starred_url': 'https://api.github.com/users/luandy64/starred{/owner}{/repo}',
                                     'subscriptions_url': 'https://api.github.com/users/luandy64/subscriptions',
                                     'type': 'User',
                                     'url': 'https://api.github.com/users/luandy64'},
                         'description': None,
                         'due_on': None,
                         'html_url': 'https://github.com/singer-io/tap-github/milestone/1',
                         'id': 6398418,
                         'labels_url': 'https://api.github.com/repos/singer-io/tap-github/milestones/1/labels',
                         'node_id': 'MDk6TWlsZXN0b25lNjM5ODQxOA==',
                         'number': 1,
                         'open_issues': 1,
                         'state': 'open',
                         'title': 'new-feature',
                         'updated_at': '2021-02-05T15:49:48Z',
                         'url': 'https://api.github.com/repos/singer-io/tap-github/milestones/1'},

[daigotanaka]

@luandy64 Thx for reviewing. My sample data didn't have milestones. I parsed your example and created the (sub) schema using https://pypi.org/project/getschema/

Your example contained due_on: None, so I manually changed it to date-time.

[luandy64]

Thank you, the bane of my existence is creating test data to validate these schemas