build: Update ZooKeeper to 3.9.4 to resolve vulnerability (#1281)

Author: abhisranjan

pom.xml

@@ -72,7 +72,7 @@
         <redirectTestOutputToFile>true</redirectTestOutputToFile>
 
         <!-- versions -->
-        <zookeeper-version>3.9.3</zookeeper-version>
+        <zookeeper-version>3.9.4</zookeeper-version>
         <maven-bundle-plugin-version>5.1.4</maven-bundle-plugin-version>
         <maven-compiler-plugin-version>3.10.0</maven-compiler-plugin-version>
         <maven-dependency-plugin-version>3.2.0</maven-dependency-plugin-version>