ci: fixed dependabot path (#407)

Signed-off-by: Frederic BIDON <fredbi@yahoo.com>

Author: fredbi

.github/dependabot.yaml

@@ -1,8 +1,7 @@
 version: 2
 updates:
   - package-ecosystem: "github-actions"
-    directories:
-      - "**/*"
+    directory: "/"
     schedule:
       interval: "weekly"
       day: "friday"