update int_github__pull_request_times to not drop pull requests witho…

[samkessaram]

…ut requested_reviewers

Please provide your name and company
Sam Kessaram
Zensurance

Link the issue/feature request which this PR is meant to address
#56

Detail what changes this PR introduces and how this addresses the issue/feature request linked above.
Updated a join type in int_github__pull_request_times so as to not drop pull requests that did not have explicit reviewers requested.

How did you validate the changes introduced within this PR?

• dbt tests passed in my company project
• QA query to validate that merged PRs in my company all now have valid merged_at values

Which warehouse did you use to develop these changes?
Snowflake

Did you update the CHANGELOG?

• Yes

Did you update the dbt_project.yml files with the version upgrade (please leverage standard semantic versioning)? (In both your main project and integration_tests)

• Yes

Typically there are additional maintenance changes required before this will be ready for an upcoming release. Are you comfortable with the Fivetran team making a few commits directly to your branch?

• Yes
• No

If you had to summarize this PR in an emoji, which would it be?

🍔

Feedback

We are so excited you decided to contribute to the Fivetran community dbt package! We continue to work to improve the packages and would greatly appreciate your feedback on our existing dbt packages or what you'd like to see next.

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