Make yamllint happy (#16)

## 💌 Description

Add a .yamllint file to disable the line-length rule, and add the yaml
[document
start](https://yamllint.readthedocs.io/en/stable/rules.html#module-yamllint.rules.document_start)
to actions.yaml.

Any developer that uses editors with syntax checking (specifically with
yamllint) happier.

## 🔗 Related issue

<!-- If your PR refers to a related issue, link it here. -->

## 🏗️ Type of change

<!-- Mark with an `x` all the checkboxes that apply (like `[x]`) -->

- [ ] 📚 Examples / docs / tutorials
- [ ] 🐛 Bug fix (non-breaking change which fixes an issue)
- [x] 🥂 Improvement (non-breaking change which improves an existing
feature)
- [ ] 🚀 New feature (non-breaking change which adds functionality)
- [ ] 💥 Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] 🚨 Security fix
- [ ] ⬆️ Dependencies update

## ✅ Checklist

<!-- Mark with an `x` all the checkboxes that apply (like `[x]`) -->

- [x] I've read the [`Code of
Conduct`](https://github.com/raven-actions/actionlint/blob/main/.github/CODE_OF_CONDUCT.md)>
document.
- [x] I've read the
[`Contributing`](https://github.com/raven-actions/actionlint/blob/main/.github/CONTRIBUTING.md)
guide.

Signed-off-by: Bryan Hundven <[email protected]>

.yamllint

@@ -0,0 +1,3 @@
+rules:
+  line-length:
+    disable: true

action.yml

@@ -1,3 +1,4 @@
+---
 # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions
 name: actionlint
 description: ✅ Run actionlint for validating your GitHub Actions workflow files.