move file to correct folder

[paulbadcock]

fix docker build

🗣 Description

This resolves a missing file from the repo

💭 Motivation and context

The requirements.txt is missing causing the docker build to fail.

The application won't build without it.

The file is moved from the root to the correct folder.

Closes #12

🧪 Testing

cd log4-scanner; docker build .

completes now.

✅ Pre-approval checklist

• [ ] This PR has an informative and human-readable title.
• [ ] Changes are limited to a single goal - eschew scope creep!
• [ ] All future TODOs are captured in issues, which are referenced in code comments.
• [ ] All relevant type-of-change labels have been added.
• [ ] I have read the CONTRIBUTING document.
• [ ] These code changes follow cisagov code standards.
• [ ] All relevant repo and/or project documentation has been updated to reflect the changes in this PR.
• [ ] Tests have been added and/or modified to cover the changes in this PR.
• [ ] All new and existing tests pass.

✅ Pre-merge checklist

• [ ] Revert dependencies to default branches.
• [ ] Finalize version.

✅ Post-merge checklist

• [ ] Add a tag or create a release.