Add node 6.13.0, remove node 6.12.2
Add node 6.13.0, remove node 6.12.2

source url: https://nodejs.org/dist/v6.13.0/node-v6.13.0.tar.gz
source sha256: 021e38bd96926d0e43309b2544f2175136613cbf4e05535daf54b0190da45f34

[#155196463]

cloudfoundry/nodejs-buildpack,cloudfoundry/nodejs-buildpack,cloudfoundry/nodejs-buildpack,cloudfoundry/nodejs-buildpack