Pin GitHub Actions to commit

[rxbchen]

This is an automated PR to update actions in this repo. The operation should be no-op, as we are only switching out the version tag with the matching commit SHA.

To align with industry best practices, we are going to pin Github Actions to a specific commit SHA.

To read more about why pinning actions is recommended check here.

To ensure these Actions stay to-do-date, this PR also enables Dependabot automated updates. To read more about this configuration check here.

Please reach out if you have any questions. This PR will be merged in ~1 week.

An error occurred when attempting to merge this PR

[rxbchen]

@Arkham I'm trying to pin GH Action to a commit, however the CI seems to be broken on this PR. Let me know if there is a better way to do this.

Also, if this introduces too much toil / overhead, I can just close this PR