Update NPM auth key for publishing

[zglueck]

Prerequisites

Please fulfill the following requirements before submitting an issue to this repository.

• Check the "Common Problems" page on the WorldWind website: https://worldwind.arc.nasa.gov/web/tutorials/common-problems/
• Check that your issue isn't already filed: https://github.com/NASAWorldWind/WebWorldWind/issues
• Check the WorldWind forum for common solutions: https://forum.worldwindcentral.com/forum/web-world-wind/web-world-wind-help

Description

A security issue not related to WebWorldWind caused npm to invalidate all auth keys issued before July 12, 2018. I believe the Travis key will need to be updated.

https://status.npmjs.org/incidents/dn7c1fgrr7ng

[pdavidc]

Great catch @zglueck