fix: find config path in cwd when installed globally (#1277)

Fixes #1182 

lib/config/file.js

@@ -7,7 +7,7 @@ module.exports = {
 function getConfig(env) {
   let configFile = env.RENOVATE_CONFIG_FILE || 'config';
   if (!path.isAbsolute(configFile)) {
-    configFile = `../../${configFile}`;
+    configFile = `${process.cwd()}/${configFile}`;
   }
   let config = {};
   try {