Bump spark2.version from 2.1.3 to 2.4.8

Bumps `spark2.version` from 2.1.3 to 2.4.8.

Updates `spark-streaming_2.11` from 2.1.3 to 2.4.8

Updates `spark-core_2.11` from 2.1.3 to 2.4.8

---
updated-dependencies:
- dependency-name: org.apache.spark:spark-streaming_2.11
  dependency-type: direct:production
- dependency-name: org.apache.spark:spark-core_2.11
  dependency-type: direct:production
...

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

pom.xml

@@ -63,7 +63,7 @@
     <commons.io.version>2.6</commons.io.version>
     <commons.lang.version>2.6</commons.lang.version>
     <hadoop.version>2.3.0</hadoop.version>
-    <spark2.version>2.1.3</spark2.version>
+    <spark2.version>2.4.8</spark2.version>
     <hydrator.version>2.10.0-SNAPSHOT</hydrator.version>
     <commons.version>3.8.1</commons.version>
     <salesforce.api.version>53.0.0</salesforce.api.version>