update dependencies and devDependencies

Highlights:

* remove graceful-fs dependency as it's no longer actively maintained
* update ESLint from v4 to v5
* introduce nyc-config-common to reduce boilerplates

.gitignore

@@ -1,3 +1,2 @@
-.nyc_output
 coverage
 node_modules

.travis.yml

@@ -2,4 +2,4 @@ branches:
   except: /^v\d/
 language: node_js
 node_js: node
-after_script: node_modules/.bin/nyc report --reporter=text-lcov | npx coveralls
+after_script: node_modules/.bin/nyc report | npx coveralls

index.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const {promisify} = require('util');
-const {readFile} = require('graceful-fs');
+const {readFile} = require('fs');
 
 const ARG_ERROR = 'Expected 1 or 2 arguments (<string|Buffer|URL|integer>[, <Object|string>])';
 const PATH_ERROR = 'Expected a valid file path or a file descripter to read';