Update dependabot.yml (#278)

Search also in the operator folder

Author: v1v

.github/dependabot.yml

@@ -37,8 +37,9 @@ updates:
   - package-ecosystem: "docker"
     directories:
       - '/'
+      - 'operator/*'
     reviewers:
       - "elastic/apm-agent-python"
     registries: "*"
     schedule:
-      interval: "daily"
+      interval: "daily"