[CLEANUP] Fix indentation of dependabot configuration (#547)

Rewrite file using the project style conventions of four spaces as
defined in `.editorconfig`.

Signed-off-by: Daniel Ziegenberg <[email protected]>

Author: ziegenberg

.github/dependabot.yml

@@ -2,15 +2,15 @@
 
 version: 2
 updates:
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "daily"
+    - package-ecosystem: "github-actions"
+      directory: "/"
+      schedule:
+          interval: "daily"
 
-  - package-ecosystem: "composer"
-    directory: "/"
-    schedule:
-        interval: "daily"
-    allow:
-        - dependency-type: "development"
-    versioning-strategy: "increase"
+    - package-ecosystem: "composer"
+      directory: "/"
+      schedule:
+          interval: "daily"
+      allow:
+          - dependency-type: "development"
+      versioning-strategy: "increase"