build: fix indentation Dependabot file

Signed-off-by: Hidde Beydals <hidde@hhh.computer>

.github/dependabot.yaml

@@ -11,7 +11,7 @@ updates:
       # Group all updates together, so that they are all applied in a single PR.
       # xref: https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#groups
       docker:
-          patterns:
+        patterns:
           - "*"
 
   - package-ecosystem: "github-actions"