Update yargs to version 12.0.1 (postcss#224)

Remove hack since yargs bug is finally fixed

Author: greenkeeper[bot]

lib/args.js

@@ -56,9 +56,6 @@ Usage:
     alias: 'replace',
     desc: 'Replace (overwrite) the input file',
     type: 'boolean',
-    // HACK: conflicts doesn't work with boolean opts correctly, so we do this
-    // See https://github.com/yargs/yargs/issues/929
-    coerce: v => v || undefined,
     conflicts: ['output', 'dir']
   })
   .alias('map', 'm')
@@ -72,9 +69,6 @@ Usage:
     alias: 'w',
     desc: 'Watch files for changes and recompile as needed',
     type: 'boolean',
-    // HACK: conflicts doesn't work with boolean opts correctly, so we do this
-    // See https://github.com/yargs/yargs/issues/929
-    coerce: v => v || undefined,
     conflicts: 'replace'
   })
   .option('env', {

package.json

@@ -29,7 +29,7 @@
     "postcss-reporter": "^5.0.0",
     "pretty-hrtime": "^1.0.3",
     "read-cache": "^1.0.0",
-    "yargs": "^11.0.0"
+    "yargs": "^12.0.1"
   },
   "devDependencies": {
     "ava": "^0.25.0",