Upgrade rxjava2 2.2.19

Author: slandelle

pom.xml

@@ -472,7 +472,7 @@
     <activation.version>1.2.2</activation.version>
     <netty-reactive-streams.version>2.0.4</netty-reactive-streams.version>
     <rxjava.version>1.3.8</rxjava.version>
-    <rxjava2.version>2.2.18</rxjava2.version>
+    <rxjava2.version>2.2.19</rxjava2.version>
     <logback.version>1.2.3</logback.version>
     <testng.version>7.1.0</testng.version>
     <jetty.version>9.4.18.v20190429</jetty.version>