chore(deps): update node.js to v21.6

Author: renovate[bot]

.circleci/config.yml

@@ -17,7 +17,7 @@ jobs:
   build:
     working_directory: ~/nest
     docker:
-      - image: cimg/node:21.1
+      - image: cimg/node:21.6
     steps:
       - checkout
       - run:
@@ -39,7 +39,7 @@ jobs:
   integration_tests:
     working_directory: ~/nest
     docker:
-      - image: cimg/node:21.1
+      - image: cimg/node:21.6
     steps:
       - checkout
       - *restore-cache