Update postcss-load-config to version 2.0.0

Remove usage of argv option; it has been removed from
postcss-load-config and the default behavior is what we want

Author: greenkeeper[bot]

index.js

@@ -125,9 +125,7 @@ Promise.resolve()
 function rc(ctx, path) {
   if (argv.use) return Promise.resolve(cliConfig)
 
-  // Set argv: false to keep cosmiconfig from attempting to read the --config
-  // flag from process.argv
-  return postcssrc(ctx, path, { argv: false })
+  return postcssrc(ctx, path)
     .then(rc => {
       if (rc.options.from || rc.options.to) {
         error(

package.json

@@ -25,7 +25,7 @@
     "get-stdin": "^6.0.0",
     "globby": "^8.0.0",
     "postcss": "^7.0.0",
-    "postcss-load-config": "^1.1.0",
+    "postcss-load-config": "^2.0.0",
     "postcss-reporter": "^5.0.0",
     "pretty-hrtime": "^1.0.3",
     "read-cache": "^1.0.0",