package.json: fix invalid syntax in `engines` (#1666)
package.json: fix invalid syntax in `engines` (#1666)

`!` is not supported by the semver library. This fixes a regression in v7
when used with engine-strict mode.

While the change in this PR may look similar to the state before #1660, 
it differs by using two pipe characters instead of one.
visionmedia/superagent,visionmedia/superagent,visionmedia/superagent