Potential to be affected by secondary rate limits

[cicirello]

Describe the bug
There is potential for the rate limit on the code search API to interact with some other GitHub secondary rate limits. This issue probably won't turn up under most normal use-cases of the action. It came up under development, when multiple push events triggered test cases multiple times within relatively short timespan.

To Reproduce
Steps to reproduce the behavior:

1. Configure a workflow that monitors multiple actions.
2. Run the workflow multiple times in succession.
3. Observe the secondary rate limit error message.

Expected behavior
Decrease likelihood of hitting rate limit (perhaps by adding a delay between queries).