chore: .npmrc

[breautek]

Platforms affected

N/A

Motivation and Context

Progresses apache/cordova#299

Ensures that the official NPM registry is used when installing packages for contributors that uses a more complicated NPM environment configuration.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary