passim: update travis-ci configuration and references

travis-ci.com replaces travis-ci.org, which is no longer active.  Also
update the configuration for modern Node versions and to support
testing other branches.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>

.travis.yml

@@ -1,9 +1,17 @@
 language: node_js
 node_js:
   - "node"
+  - "16"
+  - "14"
+  - "12"
   - "8"
-  - "6"
+  - "5"
   - "4"
+branches:
+  only:
+    - master
+    - next
+    - pu
 after_success:
   - npm run eslint
   - npm run coveralls

CHANGELOG.md

@@ -210,7 +210,7 @@
 [issue#21]: https://github.com/pabigot/buffer-layout/issues/21
 [pr#24]: https://github.com/pabigot/buffer-layout/pull/24
 [pr#26]: https://github.com/pabigot/buffer-layout/pull/26
-[ci:travis]: https://travis-ci.org/pabigot/buffer-layout
+[ci:travis]: https://travis-ci.com/pabigot/buffer-layout
 [ci:coveralls]: https://coveralls.io/github/pabigot/buffer-layout
 [node:issue#3992]: https://github.com/nodejs/node/issues/3992
 [node:issue#3994]: https://github.com/nodejs/node/issues/3994

README.md

@@ -1,7 +1,7 @@
 # buffer-layout
 
 [![NPM version](https://img.shields.io/npm/v/buffer-layout.svg)](https://www.npmjs.com/package/buffer-layout "View this project on NPM")
-[![Build Status](https://travis-ci.org/pabigot/buffer-layout.svg?branch=master)](https://travis-ci.org/pabigot/buffer-layout "Check build status on TravisCI")
+[![Build Status](https://travis-ci.com/pabigot/buffer-layout.svg?branch=master)](https://travis-ci.com/pabigot/buffer-layout "Check build status on TravisCI")
 [![Coverage Status](https://coveralls.io/repos/pabigot/buffer-layout/badge.svg?branch=master&service=github)](https://coveralls.io/github/pabigot/buffer-layout?branch=master "Check coverage status on Coveralls")
 
 buffer-layout is a utility module implemented in pure JavaScript that