[examples] fix env variables names

Author: capcom6

configs/config.example.yml

@@ -17,8 +17,8 @@ database: # database
   max_idle_conns: 2 # database max idle connections (default: 2 * CPU) [DATABASE__MAX_IDLE_CONNS]
 fcm: # firebase cloud messaging config
   credentials_json: "{}" # firebase credentials json (for public mode only) [FCM__CREDENTIALS_JSON]
-  timeout_seconds: 1 # push notification send timeout [FCM__DEBOUNCE_SECONDS]
-  debounce_seconds: 5 # push notification debounce (>= 5s) [FCM__TIMEOUT_SECONDS]
+  timeout_seconds: 1 # push notification send timeout [FCM__TIMEOUT_SECONDS]
+  debounce_seconds: 5 # push notification debounce (>= 5s) [FCM__DEBOUNCE_SECONDS]
 tasks: # tasks config
   hashing: # hashing task (hashes processed messages for privacy purposes)
     interval_seconds: 15 # hashing interval in seconds [TASKS__HASHING__INTERVAL_SECONDS]