fix(dependabot): Remove invalid registries section from config (#41)

Remove the registries block from .github/dependabot.yml which was missing
the required username and password properties. This change ensures that
Dependabot parses the configuration correctly and operates without error.

Author: MarjovanLier

.github/dependabot.yml

@@ -1,13 +1,7 @@
 version: 2
-registries:
-  packagist:
-    type: composer-repository
-    url: "https://repo.packagist.org"
 updates:
   - package-ecosystem: "composer"
     directory: "/"
-    registries:
-      - packagist
     schedule:
       interval: "daily"
     commit-message: