Upgrade rxjava 1.3.8

Author: slandelle

pom.xml

@@ -405,7 +405,7 @@
     <reactive-streams.version>1.0.2</reactive-streams.version>
     <activation.version>1.2.0</activation.version>
     <netty-reactive-streams.version>2.0.0</netty-reactive-streams.version>
-    <rxjava.version>1.3.6</rxjava.version>
+    <rxjava.version>1.3.8</rxjava.version>
     <rxjava2.version>2.1.14</rxjava2.version>
     <logback.version>1.2.3</logback.version>
     <testng.version>6.13.1</testng.version>