Upgrade rxjava2 2.1.13

Author: slandelle

pom.xml

@@ -402,7 +402,7 @@
     <reactive-streams.version>1.0.2</reactive-streams.version>
     <netty-reactive-streams.version>2.0.0</netty-reactive-streams.version>
     <rxjava.version>1.3.6</rxjava.version>
-    <rxjava2.version>2.1.9</rxjava2.version>
+    <rxjava2.version>2.1.13</rxjava2.version>
     <logback.version>1.2.3</logback.version>
     <testng.version>6.13.1</testng.version>
     <jetty.version>9.4.8.v20171121</jetty.version>