docs(readme): update env variable TASK_CRON_SYNC

README.md

@@ -164,13 +164,13 @@ The following is a list of environment variables you can tell within your Docker
 > ✔️ Correct
 > ```yml
 > environment:
->    - CRON_TIME=*/60 * * * *
+>    - TASK_CRON_SYNC=*/60 * * * *
 > ```
 >
 > ❌ Incorrect
 > ```yml
 > environment:
->    - CRON_TIME="*/60 * * * *"
+>    - TASK_CRON_SYNC="*/60 * * * *"
 > ```
 
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