Dependabot config: fix yaml warnings

Author: jrfnl

.github/dependabot.yml

@@ -3,13 +3,14 @@
 # Please see the documentation for all configuration options:
 # https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
 
+---
 version: 2
 updates:
   - package-ecosystem: "composer"
     directory: "/"
     schedule:
       interval: "weekly"
-    open-pull-requests-limit: 5 # Set to 0 to (temporarily) disable.
+    open-pull-requests-limit: 5
     versioning-strategy: widen
     allow:
       # Only allow updates to the dev dependencies as non-dev dependency