bump connector/j version (#706)

Author: lesv

appengine-java8/cloudsql/pom.xml

@@ -71,7 +71,7 @@
     <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
-      <version>5.1.40</version>  <!-- v5.x.x is for production, v6.x.x EAP X DevAPI -->
+      <version>5.1.42</version>  <!-- v5.x.x is for production, v6.x.x EAP X DevAPI -->
       <!--<version>6.0.6</version>-->
     </dependency>
     <dependency>