[CI] Autostart CI when a Dockerfile is modified

.gitlab-ci.yml

@@ -58,10 +58,14 @@ set-variables:
   # If there are changes in any of the files and folders of 'pica-*' or
   # 'meta-*', then propose a manual build
   rules:
+    - changes:
+      - "pica-*/Dockerfile"
+      - "meta-*/Dockerfile"
+      when: always
     - changes:
       - "pica-*/**"
-      - "meta-*/**"
       when: manual
+      allow_failure: true
 
 # Build the image that was modified
 build: