fix github connector: use composite key for workflow runs to keep all attempt

[scauglog]

What

Currently the github connector randomly keep workflow runs rows when there are many attempt for the same workflow run.

How

The correct primary key to use to keep all attempts is the combination of the id of the workflow run and the number of attempt run_attempt

Review guide

User Impact

User will always have all attempt.

Can this PR be safely reverted and rolled back?

• [X] YES 💚
• [ ] NO ❌