build: use config file for linkinator (#383)

Author: JustinBeckwith

linkinator.config.json

@@ -0,0 +1,7 @@
+{
+  "recurse": true,
+  "skip": [
+    "https://codecov.io/gh/googleapis/",
+    "www.googleapis.com"
+  ]
+}

package.json

@@ -29,7 +29,7 @@
     "prepare": "npm run compile",
     "pretest": "npm run compile",
     "license-check": "jsgl --local .",
-    "docs-test": "linkinator docs --recurse",
+    "docs-test": "linkinator docs",
     "predocs-test": "npm run docs"
   },
   "dependencies": {
@@ -79,7 +79,7 @@
     "js-green-licenses": "^1.1.0",
     "json-stable-stringify": "^1.0.1",
     "koa": "^2.7.0",
-    "linkinator": "^1.4.3",
+    "linkinator": "^1.5.0",
     "lodash.maxby": "^4.6.0",
     "lodash.merge": "^4.6.1",
     "lodash.omit": "^4.5.0",