Segmentation fault pg_cron_unschedule

```2021-01-29 16:39:12.135 MSK [64352] LOG: cron job 537 COMMAND completed: CALL
2021-01-29 16:39:12.149 MSK [15046] LOG: background worker "pg_cron launcher" (PID 64352) was terminated by signal 11: Segmentation fault
2021-01-29 16:39:12.149 MSK [15046] LOG: terminating any other active server processes
2021-01-29 16:39:12.149 MSK [65302] WARNING: terminating connection because of crash of another server process
2021-01-29 16:39:12.149 MSK [65302] DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2021-01-29 16:39:12.149 MSK [65302] HINT: In a moment you should be able to reconnect to the database and repeat your command.
2021-01-29 16:39:12.394 MSK [65882] FATAL: the database system is in recovery mode
2021-01-29 16:39:12.444 MSK [15046] LOG: all server processes terminated; reinitializing
2021-01-29 16:39:13.293 MSK [65883] LOG: database system was interrupted; last known up at 2021-01-29 16:33:06 MSK
2021-01-29 16:39:13.294 MSK [65886] FATAL: the database system is in recovery mode
```

1. in Java created cron task with timer every 1 min. to call procedure and get task id
2. update task id field in user table (no anybody change that value)
3. in the end of procedure call pg_cron_unschedule with that value id from user table

#74