chore!: remove main export mungeUtil (#126)

Removes `mungeUtil` from the list of modules that are exported by
`cordova-common`. It was documented as _internal_ and we did not use it in any
of our repos.

README.md

@@ -143,7 +143,6 @@ PlatformJson
 ConfigChanges
 ConfigKeeper
 ConfigFile
-mungeUtil
 ```
 
 ## Setup

cordova-common.js

@@ -37,7 +37,6 @@ module.exports = {
     get ConfigChanges () { return require('./src/ConfigChanges/ConfigChanges'); },
     get ConfigKeeper () { return require('./src/ConfigChanges/ConfigKeeper'); },
     get ConfigFile () { return require('./src/ConfigChanges/ConfigFile'); },
-    get mungeUtil () { return require('./src/ConfigChanges/munge-util'); },
 
     get xmlHelpers () { return require('./src/util/xml-helpers'); }
 };