[BUG] Reek missing `detectors` key

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**Before we start...:**

- [x] I checked the documentation and found no answer
- [x] I checked to make sure that this issue has not already been filed
- [x] I'm reporting the issue to the correct repository (for multi-repository projects)

**Version, Branch, or Commit:**

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**Expected behavior:**

1. Create a new project with this template
2. Run bin/setup
3. Commit changes without any errors or problems

**Actual behavior:**

When I try to commit after running the bin/setup script I see an error message:
`reek key 'Attribute:' is undefined.`

According to the documentation over here:
https://github.com/troessner/reek/blob/master/docs/Reek-4-to-Reek-5-migration.md#reek-4-to-reek-5-migration

Reek 5 now requires a `detectors` key for standalone detectors.

So I think we just need to update the .reek.yml file.

**Steps to reproduce:**

How do I achieve this behavior? Use the following format to provide a step-by-step guide:

1. Step 1: I use the template to create a new project
2. Step 2: I run bin/setup
3. Step: 3: I try to commit all changes
4. Step 4: I see an error message `reek key 'Attribute:' is undefined.`

**Context and environment:**

Provide any relevant information about your setup (Customize the list accordingly based on what info is relevant to this project)

1. Version of the software the issue is being opened for. Reek 5
4. Ruby version: 3.01

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