Automatically lint *.cjs files

Fixes: standard/standard#1009

Author: feross

bin/cmd.js

@@ -50,7 +50,7 @@ function Cli (opts) {
 Usage:
     ${opts.cmd} <flags> [FILES...]
 
-    If FILES is omitted, then all JavaScript source files (*.js, *.jsx, *.mjs)
+    If FILES is omitted, all JavaScript source files (*.js, *.jsx, *.mjs, *.cjs)
     in the current working directory are checked, recursively.
 
     Certain paths (node_modules/, coverage/, vendor/, *.min.js, bundle.js, and

index.js

@@ -12,7 +12,8 @@ var HOME_OR_TMP = os.homedir() || os.tmpdir()
 var DEFAULT_PATTERNS = [
   '**/*.js',
   '**/*.jsx',
-  '**/*.mjs'
+  '**/*.mjs',
+  '**/*.cjs'
 ]
 
 var DEFAULT_IGNORE = [