message: Remove the timezone from the field type as no builder fits it
diff: @@ -154,7 +154,7 @@ impl ArrowAssoc for DateTime<Utc> {
  fn field(header: &str) -> Field {
  Field::new(
  header,
  - ArrowDataType::Timestamp(TimeUnit::Nanosecond, Some("UTC".to_string())),
  + ArrowDataType::Timestamp(TimeUnit::Nanosecond, None),
  true,
  )
  }
  @@ -175,7 +175,7 @@ impl ArrowAssoc for Option<DateTime<Utc>> {
  fn field(header: &str) -> Field {
  Field::new(
  header,
  - ArrowDataType::Timestamp(TimeUnit::Nanosecond, Some("UTC".to_string())),
  + ArrowDataType::Timestamp(TimeUnit::Nanosecond, None),
  false,
  )
  }
  