Bump spark.version from 1.6.1 to 2.2.3 in /templates

Bumps `spark.version` from 1.6.1 to 2.2.3.

Updates `spark-core_2.10` from 1.6.1 to 2.2.3

Updates `spark-hive_2.10` from 1.6.1 to 2.2.3

Updates `spark-sql_2.10` from 1.6.1 to 2.2.3

Updates `spark-streaming_2.10` from 1.6.1 to 2.2.3

Updates `spark-yarn_2.10` from 1.6.1 to 2.2.3

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

templates/pom.xml

@@ -89,7 +89,7 @@
     <scalatest.version>2.2.1</scalatest.version>
     <scala-maven-plugin.version>3.2.2</scala.maven.plugin.version>
     <slf4j.version>1.7.16</slf4j.version>
-    <spark.version>1.6.1</spark.version>
+    <spark.version>2.2.3</spark.version>
     <spring.version>4.2.5.RELEASE</spring.version>
     <typesafe.config.version>1.3.0</typesafe.config.version>