Update cache settings

* Add kaniko cache
* Add pdm cache

.gitlab-ci.yml

@@ -25,9 +25,13 @@ workflow:
 # Use build cache to speed up CI
 default:
   cache:
-    - key: $CI_COMMIT_REF_SLUG
+    - key: "kaniko-default"
+      paths:
+        - .cache/kaniko
+    - key: "python-default"
       paths:
         - .cache/pip
+        - .cache/pdm
     - key:
         files:
           - src/plainui/yarn.lock