Update moment in our dependency graph to 2.19.3

[urbanslug]

Patch our dependency graph in regards to https://nvd.nist.gov/vuln/detail/CVE-2017-18214

Our package-lock.json shows that in our dependency tree we depend on moment@2.19.1 however this version of moment has a known vulnerability as described moment/moment#4163

The packages depending on moment are those that botkit depends on specifically:

• chrono-node
• ink-docstrap
• joi

Updating the version of botkit that we depend on could fix this but we might have to create issues under those specific packages.

Output from npm outdated currently is:

Package     Current  Wanted  Latest  Location
botkit        0.6.6   0.6.6  0.6.11  borq
i18next       9.1.0   9.1.0  10.5.0  borq
node-fetch    1.7.3   1.7.3   2.1.1  borq