Fix CI tests that dependended on Node 10 (#582)
Fix CI tests that dependended on Node 10 (#582)

These tests use >= version requirements, so they would break whenever
new major versions are released. That's not really necessary, so this
removes the bits that will continually break.
heroku/heroku-buildpack-nodejs,Scalingo/nodejs-buildpack,heroku/heroku-buildpack-nodejs,heroku/heroku-buildpack-nodejs,Scalingo/nodejs-buildpack,heroku/heroku-buildpack-nodejs,Scalingo/nodejs-buildpack,Scalingo/nodejs-buildpack,Scalingo/nodejs-buildpack,heroku/heroku-buildpack-nodejs