fix: 配合 auto-devops 變數命名，修改為 DATABASE_URL

Author: zx1986

config.py

@@ -64,14 +64,7 @@
 BOT_EXTRA_STORAGE_PLUGINS_DIR = BOT_ROOT_DIR + "/storages"
 
 STORAGE = 'SQL'
-STORAGE_CONFIG = {
-    'data_url': 'mysql+pymysql://{}:{}@{}/{}?chartset=utf8mb4'.format(
-        os.environ(DB_USERNAME),
-        os.environ(DB_PASSWORD),
-        os.environ(DB_HOST),
-        os.environ(DB_NAME)
-    ),
-}
+STORAGE_CONFIG = { 'data_url': os.environ["DATABASE_URL"] }
 
 # The location where all of Err's data should be stored. Make sure to set
 # this to a directory that is writable by the user running the bot.