Switch to uber/npm-shrinkwrap for npm-shrinkwrap.json generation

Instead of our homegrown grunt/shrinkwrap.js
Fixes #13483.
New npm-shrinkwrap.json is human-readable but still in a consistent/stable format.
Should aid debugging, produce better diffs, and be less prone to merge conflicts

test-infra/README.md

@@ -15,7 +15,7 @@ Similar to git, `s3_cache.py` makes the assumption that [SHA-256 will effectivel
 ### For Bootstrap specifically
 `s3_cache.py` is used to cache the npm packages that our Grunt tasks depend on and the RubyGems that Jekyll depends on. (Jekyll is needed to compile our docs to HTML so that we can run them thru an HTML5 validator.)
 
-For npm, the `node_modules` directory is cached based on our `npm-shrinkwrap.canonical.json` file.
+For npm, the `node_modules` directory is cached based on our `npm-shrinkwrap.json` file.
 
 For RubyGems, the `gemdir` of the current RVM-selected Ruby is cached based on the `pseudo_Gemfile.lock` file generated by our Travis build script.
 `pseudo_Gemfile.lock` contains the versions of Ruby and Jekyll that we're using (read our `.travis.yml` for details).

test-infra/S3Cachefile.json

@@ -1,6 +1,6 @@
 {
     "npm-modules": {
-        "key": "./npm-shrinkwrap.canonical.json",
+        "key": "./npm-shrinkwrap.json",
         "cache": "../node_modules",
         "generate": "./uncached-npm-install.sh"
     },

test-infra/uncached-npm-install.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 set -e
 cd ..  # /bootstrap/
-cp test-infra/npm-shrinkwrap.canonical.json npm-shrinkwrap.json
+cp test-infra/npm-shrinkwrap.json npm-shrinkwrap.json
 npm install
 rm npm-shrinkwrap.json