Remove travis CI config

Signed-off-by: Yukai Huang <yukaihuangtw@gmail.com>

.travis.yml

@@ -1,32 +0,0 @@
-language: node_js
-
-node_js:
-  - "lts/dubnium"
-  - "11"
-  - "12"
-
-dist: xenial
-cache: npm
-
-matrix:
-  fast_finish: true
-  include:
-    - node_js: lts/dubnium
-  allow_failures:
-    - node_js: "11"
-    - node_js: "12"
-
-script:
-  - npm run test:ci
-  - npm run build
-
-jobs:
-  include:
-    - stage: doctoc-check
-      install: npm install -g doctoc
-      if: type = pull_request OR branch = master
-      script:
-        - cp README.md README.md.orig
-        - npm run doctoc
-        - diff -q README.md README.md.orig
-      node_js: lts/carbon