[buildkite] Update S3 credential handling

[staticfloat]

We were alerted that our S3 credentials had leaked in a build that dumps
the environment when it errors out [0]. This PR rotates to a new key,
and also wipes out the key in the environment during the build itself,
so that sensitive values won't get written out in debugging information
like that.

[0] https://github.com/SciML/SciMLBenchmarksOutput/blob/8d80b1840228c63e8c6fdc597049211a8b916dea/markdown/DynamicalODE/single_pendulums.md

[ai-maintainer]

AI-Maintainer Review for PR - [buildkite] Update S3 credential handling

👍 Title and Description

The Title and Description are Clear and Informative

The title and description of the pull request are clear and informative. They effectively communicate the purpose of the changes, which is to update the S3 credential handling due to a previous leak. The description provides a link to the issue that prompted the update, which is helpful for understanding the context of the changes.

👍 Scope of Changes

The Changes are Narrowly Focused

The changes in this pull request are narrowly focused on updating the S3 credential handling. The modifications to the .buildkite/run_benchmark.yml file and the benchmarks/Testing/test.jmd file are specifically related to the S3 access key and secret access key. There are no indications that the author is trying to resolve multiple issues simultaneously.

❓ Testing

Testing Details are Not Provided

The description of the pull request does not provide details on how the author tested the changes. It would be beneficial to include information on the testing performed to ensure the changes effectively address the issue and do not introduce new issues.

👍 Documentation

No New Functions, Classes, or Methods Added

Based on the provided diff, there are no newly added functions, classes, or methods. Therefore, there are no docstrings that need to be added.

💡 Recommendations

Please provide details on how the changes were tested. This could include information on any local testing performed, unit tests added or updated, or other testing methods used. This will help reviewers understand the impact of the changes and ensure they effectively address the issue.

Also, please ensure that the new S3 credentials are securely stored and not exposed in any public logs or debugging information. This is crucial for maintaining the security of the system.

Reviewed with AI Maintainer

[staticfloat]

Looks good now!

[ChrisRackauckas]

Thanks!