CircleCI: Restore from cache on demo-deploy job

Author: Xenonym

.circleci/config.yml

@@ -26,6 +26,11 @@ jobs:
     working_directory: ~/repo
     steps:
       - checkout
+      - restore_cache:
+          keys:
+            - v1-dependencies-{{ checksum "package.json" }}
+            # fallback to using the latest cache if no exact match is found
+            - v1-dependencies-
       - run:
           name: Install jsonpanel-next dependencies
           command: npm install