chore: upgrade yargs-parser (#633)

* chore: upgrade yargs-parser
BREAKING CHANGE: coerce is now applied as a final step after other parsing is complete

* add documentation for breaking changes in yargs-parser@4

* fix: a few small editing nits

* fix: bump yargs-parser again

README.md

@@ -461,10 +461,17 @@ command line for `key`.
 The coercion function should accept one argument, representing the parsed value
 from the command line, and should return a new value or throw an error. The
 returned value will be used as the value for `key` (or one of its aliases) in
-`argv`. If the function throws, the error will be treated as a validation
+`argv`.
+
+If the function throws, the error will be treated as a validation
 failure, delegating to either a custom [`.fail()`](#fail) handler or printing
 the error message in the console.
 
+Coercion will be applied to a value after
+all other modifications, such as [`.normalize()`](#normalize).
+
+_Examples:_
+
 ```js
 var argv = require('yargs')
   .coerce('file', function (arg) {
@@ -495,6 +502,22 @@ var argv = require('yargs')
   .argv
 ```
 
+If you are using dot-notion or arrays, .e.g., `user.email` and `user.password`,
+coercion will be applied to the final object that has been parsed:
+
+```js
+// --user.name Batman --user.password 123
+// gives us: {name: 'batman', password: '[SECRET]'}
+var argv = require('yargs')
+  .option('user')
+  .coerce('user', opt => {
+    opt.name = opt.name.toLowerCase()
+    opt.password = '[SECRET]'
+    return opt
+  })
+  .argv
+```
+
 .command(cmd, desc, [builder], [handler])
 -----------------------------------------
 .command(cmd, desc, [module])

package.json

@@ -24,7 +24,7 @@
     "which-module": "^1.0.0",
     "window-size": "^0.2.0",
     "y18n": "^3.2.1",
-    "yargs-parser": "^3.2.0"
+    "yargs-parser": "^4.0.2"
   },
   "devDependencies": {
     "chai": "^3.4.1",