🏗️ incorporate check-html task into CI

Author: DerekNonGeneric

.nvmrc

@@ -0,0 +1 @@
+14.8

.travis.yml

@@ -1,9 +1,27 @@
-language: node_js
-node_js:
-  - "8"
+language: ruby
+
+sudo: required
+
+addons:
+  apt:
+    packages:
+      - wget
+      - curl
+
+jdk:
+  - openjdk14
+
+before_install:
+  - wget -qO- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
+  - source ~/.bashrc
+  - nvm install 14.8
+  - node --version
 
 install:
+  - bundle install
+  - gem install jekyll
   - travis_retry npm install
 
 script:
   - npm run lint
+  - npm run check:html

package.json

@@ -8,6 +8,7 @@
     "lint": "npm run lint:js && npm run lint:scss",
     "lint:js": "prettier -c --loglevel warn **/*.js",
     "lint:scss": "stylelint _sass",
+    "check:html": "bundle exec jekyll build && node _tasks/check-html.mjs",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "repository": {
@@ -20,6 +21,9 @@
     "url": "https://github.com/tc39/tc39.github.io/issues"
   },
   "homepage": "https://tc39.es/",
+  "engines": {
+    "node": "14.8"
+  },
   "devDependencies": {
     "prettier": "^1.17.1",
     "stylelint": "^10.0.1",