try to fix CI build

error:
  Installing npm packages using pnpm version ERROR: This version of pnpm
requires at least Node.js v16.14E
  The current version of Node.js is v14.21.3E

Author: omnibs

.github/workflows/CI.yml

@@ -18,7 +18,7 @@ jobs:
         version: ^6.10
     - uses: actions/setup-node@v2
       with:
-        node-version: '14'
+        node-version: '16'
         cache: 'pnpm'
     - run: pnpm install
     - run: pnpm run postinstall