[SPARK-25570][SQL][TEST] Replace 2.3.1 with 2.3.2 in HiveExternalCatalogVersionsSuite

## What changes were proposed in this pull request?

This PR aims to prevent test slowdowns at `HiveExternalCatalogVersionsSuite` by using the latest Apache Spark 2.3.2 link because the Apache mirrors will remove the old Spark 2.3.1 binaries eventually. `HiveExternalCatalogVersionsSuite` will not fail because [SPARK-24813](https://issues.apache.org/jira/browse/SPARK-24813) implements a fallback logic. However, it will cause many trials and fallbacks in all builds over `branch-2.3/branch-2.4/master`. We had better fix this issue.

## How was this patch tested?

Pass the Jenkins with the updated version.

Closes apache#22587 from dongjoon-hyun/SPARK-25570.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: hyukjinkwon <[email protected]>

Author: dongjoon-hyun

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveExternalCatalogVersionsSuite.scala

@@ -206,7 +206,7 @@ class HiveExternalCatalogVersionsSuite extends SparkSubmitTestUtils {
 
 object PROCESS_TABLES extends QueryTest with SQLTestUtils {
   // Tests the latest version of every release line.
-  val testingVersions = Seq("2.1.3", "2.2.2", "2.3.1")
+  val testingVersions = Seq("2.1.3", "2.2.2", "2.3.2")
 
   protected var spark: SparkSession = _