Upgrade node.js version for Heroku
Upgrade node.js version for Heroku

The Node.js team has announced that a high severity remote Denial of
Service (DoS) Constant Hashtable Seeds vulnerability in Node.js
versions 4.x through 8.x has been patched in the following versions:
6.11.1

dwpdigitaltech/hrt-prototype,joelanman/govuk_prototype_kit,hannalaakso/accessible-timeout-warning,dwpdigitaltech/hrt-prototype,hannalaakso/accessible-timeout-warning,alphagov/govuk_prototype_kit,benjeffreys/hmcts-idam-proto,hannalaakso/accessible-timeout-warning,benjeffreys/hmcts-idam-proto,joelanman/govuk_prototype_kit,DilwoarH/GDS-Prototype-DM-SavedSearch,DilwoarH/GDS-Prototype-DM-SavedSearch,alphagov/govuk_prototype_kit,benjeffreys/hmcts-idam-proto,alphagov/govuk_prototype_kit,DilwoarH/GDS-Prototype-DM-SavedSearch,gavinwye/govuk_prototype_kit,gavinwye/govuk_prototype_kit,joelanman/govuk_prototype_kit,dwpdigitaltech/hrt-prototype