ci(travis): improves build speed (#317)

Author: juancarlostong

.travis.yml

@@ -59,9 +59,8 @@ stages:
 jobs:
   include:
     - stage: 'Lint markdown files'
-      language: ruby
-      rvm: 2.4.1
       os: linux
+      language: generic
       install: gem install awesome_bot
       before_script: skip
       script:
@@ -70,14 +69,13 @@ jobs:
         email: false
 
     - stage: 'Lint markdown files'
-      language: node_js
-      node_js: 12
       os: linux
+      language: generic
       before_install: skip
       install:
         - npm i -g markdown-spellcheck
       before_script:
-        - wget --quiet https://gist.githubusercontent.com/juancarlostong/dad02feeebc8763af35b4fdc717cf7a2/raw/.spelling 
+        - wget --quiet https://raw.githubusercontent.com/optimizely/mdspell-config/master/.spelling
       script:
         - mdspell -a -n -r --en-us '**/*.md'
       after_success: skip