[Dependabot] Use multi-directory config for docker

.github/dependabot.yml

@@ -21,17 +21,14 @@ updates:
         - "*"
 
 - package-ecosystem: docker
-  directory: /examples/deployment/docker/db_client
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
-- package-ecosystem: docker
-  directory: /examples/deployment/docker/db_server
+  directories:
+    - /examples/deployment/docker/db_client
+    - /examples/deployment/docker/db_server
+    - /examples/deployment/docker/envsubst
+    - /examples/deployment/docker/log_server
+    - /examples/deployment/docker/log_signer
+    - /examples/deployment/kubernetes/mysql/image
+    - /integration/cloudbuild/testbase
   schedule:
     interval: weekly
   ignore:
@@ -43,56 +40,6 @@ updates:
       patterns:
         - "*"
 
-- package-ecosystem: docker
-  directory: /examples/deployment/docker/envsubst
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
-- package-ecosystem: docker
-  directory: /examples/deployment/docker/log_server
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
-- package-ecosystem: docker
-  directory: /examples/deployment/docker/log_signer
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
-- package-ecosystem: docker
-  directory: /examples/deployment/kubernetes/mysql/image
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
-- package-ecosystem: docker
-  directory: /integration/cloudbuild/testbase
-  schedule:
-    interval: weekly
-  groups:
-    docker-deps:
-      applies-to: version-updates
-      patterns:
-        - "*"
-
 - package-ecosystem: npm
   directory: /scripts/gcb2slack
   schedule: