Bump spark.version from 2.2.2 to 2.4.8 in /scala/maven/oss

Bumps `spark.version` from 2.2.2 to 2.4.8.

Updates `spark-core_2.11` from 2.2.2 to 2.4.8

Updates `spark-sql_2.11` from 2.2.2 to 2.4.8

Updates `spark-hive_2.11` from 2.2.2 to 2.4.8

---
updated-dependencies:
- dependency-name: org.apache.spark:spark-core_2.11
  dependency-type: direct:production
- dependency-name: org.apache.spark:spark-sql_2.11
  dependency-type: direct:production
- dependency-name: org.apache.spark:spark-hive_2.11
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

scala/maven/oss/pom.xml

@@ -11,7 +11,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <scala.version>2.11.8</scala.version>
     <scala.main.version>2.11</scala.main.version>
-    <spark.version>2.2.2</spark.version>
+    <spark.version>2.4.8</spark.version>
     <connector.version>2.0.10</connector.version>
   </properties>