[WAYANG-47] Properties Spark 2.11 updated with Spark version (#93)

diff --git a/wayang-platforms/wayang-spark/wayang-spark_2.11/pom.xml b/wayang-platforms/wayang-spark/wayang-spark_2.11/pom.xml
index 109ae58..f0f6eff 100644
--- a/wayang-platforms/wayang-spark/wayang-spark_2.11/pom.xml
+++ b/wayang-platforms/wayang-spark/wayang-spark_2.11/pom.xml
@@ -39,6 +39,10 @@
     </dependencies>
   </dependencyManagement>
 
+  <properties>
+    <spark.version>2.4.8</spark.version>
+  </properties>
+
   <dependencies>
     <dependency>
       <groupId>org.apache.spark</groupId>