Fix Main Branch Documentation Deployment Not Working (#94)

# Fix Main Branch Documentation Deployment Not Working

## ♻️ Current situation & Problem
- Deployment of the documentation on main was not working as expected.
`github.ref` did not evaluate to `main`. Needs to be changed to
`ref_name`:
https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/accessing-contextual-information-about-workflow-runs


## ⚙️ Release Notes 
- Fixed documentation deployment on main

## 📚 Documentation
- Will be deployed 🚀 

## 📝 Code of Conduct & Contributing Guidelines 

By submitting creating this pull request, you agree to follow our [Code
of
Conduct](https://github.com/StanfordSpezi/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordSpezi/.github/blob/main/CONTRIBUTING.md):
- [x] I agree to follow the [Code of
Conduct](https://github.com/StanfordSpezi/.github/blob/main/CODE_OF_CONDUCT.md)
and [Contributing
Guidelines](https://github.com/StanfordSpezi/.github/blob/main/CONTRIBUTING.md).

.github/workflows/documentation-deployment.yml

@@ -29,4 +29,4 @@ jobs:
       id-token: write
     with:
       scheme: 'TemplateApplication'
-      dryrun: ${{ github.ref != 'main' }}
+      dryrun: ${{ github.ref_name != 'main' }}