Dependabot script shouldn't be in workflows

[cpswan]

Describe the bug
at_tools/.github/workflows/dependabot.yml should be in .github not .github/workflows, resulting in failed Actions runs.

To Reproduce
Steps to reproduce the behavior:

1. Make any change in this repo
2. See that Actions is trying to run dependabot as if it's a workflow
3. Run fails resulting in failure notifications.

Expected behavior
Dependabot should not be in workflows

Screenshots