feat: Support for passing args to carlo

Ability to specify additional arguments to
carlo through an environment variable (NDB_CARLO_ARGS)

Ref GoogleChromeLabs#238

lib/launcher.js

@@ -18,6 +18,7 @@ process.on('unhandledRejection', error => {
 
 async function launch() {
   let app;
+  const carloArgs = process.env.NDB_CARLO_ARGS ? JSON.parse(process.env.NDB_CARLO_ARGS) : {};
   try {
     app = await carlo.launch({
       bgcolor: '#242424',
@@ -28,7 +29,8 @@ async function launch() {
           argv: process.argv,
           nodeExecPath: process.execPath
         })).toString('base64')
-      }
+      },
+      ...carloArgs
     });
   } catch (e) {
     if (e.message !== 'Could not start the browser or the browser was already running with the given profile.')