build: move .npmignore file to root directory

Author: Planeshifter

lib/node_modules/@stdlib/_tools/scripts/templates/workflow_productionize_cli.yml.txt

@@ -870,6 +870,7 @@ jobs:
       # Move cli directory to root:
       - name: 'Move cli directory to root'
         run: |
+          mv ./cli/.npmignore .
           mv ./cli/* .
           rmdir ./cli