ci: added alternate sources for dependabot updates

Signed-off-by: Frederic BIDON <[email protected]>

Author: fredbi

.github/dependabot.yaml

@@ -1,7 +1,10 @@
 version: 2
 updates:
   - package-ecosystem: "github-actions"
-    directory: "/"
+    directories:
+      - "/"
+      - "/ci-jobs/bot-credentials"
+      - "/ci-jobs/next-tag"
     schedule:
       interval: "daily"
     open-pull-requests-limit: 2          # <- default is 5