Add chrono::Offset import needed for .fix() method

The previous commit removed chrono::prelude::* but the Offset trait
is needed for calling .fix() on TzOffset.

Author: ShreyeshArangath

native-engine/datafusion-ext-functions/src/spark_dates.rs

@@ -20,7 +20,7 @@ use arrow::{
     compute::{DatePart, date_part},
     datatypes::{DataType, TimeUnit},
 };
-use chrono::{TimeZone, Utc};
+use chrono::{Offset, TimeZone, Utc};
 use chrono_tz::Tz;
 use datafusion::{
     common::{Result, ScalarValue},