revert to older packages

@sulkaharo found a weird json ordering problem, see nightscout#3660 and https://gitter.im/nightscout/public?at=5b3b1e16bd92d807828ecf16
This might have been caused by an incompatible package upgrade

I suspect this might have been caused by an upgrade to https://github.com/nightscout/cgm-remote-monitor/commits/dev/package.json
in the Commits on Jun 24, 2018 or Jun 25, 2018.

I reverted to nightscout@1eb54cd#diff-b9cfc7f2cdf78a7f4b91a753d10865a2 (May 18)
Only changes Use Node 10.x or Node 8.9.x and also support npm 6.1.x