to lower case env name

package.json

@@ -104,7 +104,7 @@
     "watchdog": "^0.8.1",
     "wechaty-puppet": "^0.2.12",
     "wechaty-puppet-puppeteer": "^0.2.10",
-    "wechaty-puppet-wechat4u": "^0.2.11",
+    "wechaty-puppet-wechat4u": "^0.2.13",
     "ws": "^5.2.0",
     "xml2json": "^0.11.2"
   },

src/config.ts

@@ -117,7 +117,7 @@ export class Config {
 
   public apihost = process.env['WECHATY_APIHOST']    || DEFAULT_SETTING.DEFAULT_APIHOST
   public head    = ('WECHATY_HEAD' in process.env) ? (!!process.env['WECHATY_HEAD']) : (!!(DEFAULT_SETTING.DEFAULT_HEAD))
-  public puppet  = (process.env['WECHATY_PUPPET']    || DEFAULT_SETTING.DEFAULT_PUPPET) as PuppetName
+  public puppet  = (process.env['WECHATY_PUPPET']    || DEFAULT_SETTING.DEFAULT_PUPPET).toLowerCase() as PuppetName
 
   public profile = process.env['WECHATY_PROFILE']    || null    // DO NOT set DEFAULT_PROFILE, because sometimes user do not want to save session
   public token   = process.env['WECHATY_TOKEN']      || null    // DO NOT set DEFAULT, because sometimes user do not want to connect to io cloud service