[BUG] JSQLParser 5.3 : PostgreSQL : Cannot parse DROP COLUMN command where data is the column name

### Failing SQL Feature:
- Cannot parse DROP COLUMN command where `data` is the column name
- `ALTER TABLE example DROP COLUMN data;` can't be parsed

### SQL Example:
- ```sql
    ALTER TABLE example DROP COLUMN data;
    ```

### Software Information:
- JSQLParser 5.3
- PostgreSQL

### Tips:
Appears that adding a column with name `data` works ok
