Fix formatting issues in YAML files (#20)

Author: dwydler

.yamllint

@@ -12,3 +12,7 @@ rules:
     level: warning
   line-length:
     max: 255
+  comments:
+    ignore: cloud-init.template.yml
+  document-start:
+    ignore: cloud-init.template.yml

action.yml

@@ -1,3 +1,4 @@
+---
 name: Self-Hosted GitHub Actions Runner on Hetzner Cloud
 description: A GitHub Action to automatically create Hetzner Cloud servers and register them as self-hosted GitHub Actions runners.
 author: Nils Knieling
@@ -99,9 +100,9 @@ inputs:
     required: false
     type: 'choice'
     options:
-    - repo
-    - org
-    default: 'repo'    
+      - repo
+      - org
+    default: 'repo'
   server_id:
     description: >-
       ID (integer) of Hetzner Cloud Server to delete.