Upgrade angular CLI

First of all, you need to uninstall existing angular CLI from the machine, then need to remove cache and install latest cli.
You need to execute the following commands.

npm uninstall -g angular-cli
npm cache clean or npm cache verify #(if npm > 5)
npm install -g @angular/cli@latest

If you want to update local packages as per the version of the latest CLI installed, then you need to execute following commands.

rm -rf node_modules
npm uninstall --save-dev angular-cli
npm install --save-dev @angular/cli@latest
 npm install

Hopefully, above commands will help you to upgrade angular CLI.
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