#38 Fix CI/CD build.

Author: yruslan

src/main/scala/za/co/absa/spark/hats/transformations/NestedArrayTransformations.scala

@@ -453,7 +453,7 @@ object NestedArrayTransformations {
             throw new IllegalArgumentException(s"Not a struct field: $columnToUnstruct")
         }
         if (newColumn == null) {
-          mappedFields
+          mappedFields.toSeq
         } else {
           Seq(newColumn) ++ mappedFields
         }
@@ -848,7 +848,7 @@ object NestedArrayTransformations {
           handlePrimitive(dt, transformExpression, errorExpression, parentPath, arrCtx)
       }
       if (newColumn == null) {
-        mappedFields
+        mappedFields.toSeq
       } else {
         Seq(newColumn) ++ mappedFields
       }

src/main/scala_2.11/za/co/absa/spark/hats/HofsWrapper.scala

@@ -21,7 +21,9 @@ import org.apache.spark.sql.Column
 import za.co.absa.spark.hofs.{transform => hofsTransform}
 
 /**
-  * This is a wrapper for high order functions depending on Scala version
+  * This is a wrapper for high order functions depending on Scala version.
+  *
+  * This implementation uses Hofs(https://github.com/AbsaOSS/spark-hofs).
   */
 object HofsWrapper {
   /**

src/main/scala_2.12/za/co/absa/spark/hats/HofsWrapper.scala

@@ -20,7 +20,9 @@ import org.apache.spark.sql.Column
 import org.apache.spark.sql.functions.{transform => sparkTransform}
 
 /**
-  * This is a wrapper for high order functions depending on Scala version
+  * This is a wrapper for high order functions depending on Scala version.
+  *
+  * This implementation uses native Spark transform().
   */
 object HofsWrapper {
   /**

src/main/scala_2.13/za/co/absa/spark/hats/HofsWrapper.scala

@@ -16,10 +16,13 @@
 
 package za.co.absa.spark.hats
 
-import org.apache.spark.sql.{Column, functions => sparkTransform}
+import org.apache.spark.sql.Column
+import org.apache.spark.sql.functions.{transform => sparkTransform}
 
 /**
-  * This is a wrapper for high order functions depending on Scala version
+  * This is a wrapper for high order functions depending on Scala version.
+  *
+  * This implementation uses native Spark transform().
   */
 object HofsWrapper {
   /**