[Snyk] Fix for 1 vulnerable dependency path (#4219)

The following vulnerabilities are ignored:
- https://snyk.io/vuln/npm:content-type-parser:20170905

Latest report for mozilla/addons-frontend:
https://snyk.io/test/github/mozilla/addons-frontend

.snyk

@@ -1,9 +1,11 @@
 # Snyk (https://snyk.io) policy file, patches or ignores known vulnerabilities.
-# version: v1.10.1
 # ignores vulnerabilities until expiry date; change duration by modifying expiry date
 ignore:
   'npm:content-type-parser:20170905':
     - jsdom > content-type-parser:
-        reason: 'We only use this for DOMPurify (no external fetching) so we are probably not vulnerable'
-        expires: '2018-01-12T17:51:49.204Z'
+        reason: >-
+          We only use this for DOMPurify (no external fetching) so we are
+          probably not vulnerable
+        expires: '2018-02-23T22:52:31.923Z'
 patch: {}
+version: v1.10.1

package.json

@@ -33,7 +33,8 @@
     "test-coverage-once": "bin/config-check.js && better-npm-run jest --coverage",
     "test-once": "bin/config-check.js && better-npm-run jest && npm run lint",
     "version-check": "bin/version-check.js",
-    "webpack-dev-server": "npm run build-locales && better-npm-run webpack-dev-server"
+    "webpack-dev-server": "npm run build-locales && better-npm-run webpack-dev-server",
+    "snyk-protect": "snyk protect"
   },
   "betterScripts": {
     "build": {
@@ -275,6 +276,7 @@
     "semver": "^5.3.0",
     "shelljs": "^0.7.7",
     "sinon": "^4.0.0",
+    "snyk": "^1.69.3",
     "style-loader": "^0.19.0",
     "stylelint": "^8.0.0",
     "stylelint-config-standard": "^17.0.0",
@@ -294,5 +296,6 @@
       "path": "./dist/*.js",
       "threshold": "300 Kb"
     }
-  ]
+  ],
+  "snyk": true
 }