[Typescript-Node] Date formatting using Date.toString instead of Date.toISOString()

Created by: gbrown-ce

Description

When dealing with dates in the generator it formats a date with the javascript toString method (which looks like this:

"Wed Oct 05 2011 10:48:00 GMT-0400 (Eastern Daylight Time)"

Rather than the more standardized toISOString() method:

"2011-10-05T14:48:00.000Z"

This makes dealing with dates tricky in different scenarios we have come across. The Angular client already properly uses toISOString, so there is precedent for it.

openapi-generator version

3.2.1