App should sanitize package name

[paleite]

Version

3.0.0-beta.6

Reproduction link

https://codesandbox.io/s/yp48m5w21v

Steps to reproduce

vue create " invalid name"

OR

vue create existing-tabbed-folder-name/

What is expected?

vue-cli should be able to build the app once the project is created

What is actually happening?

yarn fails, saying:
error An unexpected error occurred: "package.json: Name contains illegal characters".
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
ERROR command failed: yarn

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Yarn is unable to run because the package name contains illegal characters. I'm not sure which chars are considered illegal, but spaces and slashes definitely are.

I ran into this bug trying to add Vue to an existing folder, when I tabbed the folder-name.

vue-cli should not be able to generate a project with an invalid package name.

Please note that the link above will display the bug if you download and build the project locally. Both NPM and Yarn are affected.