#154: Adopted new Serenity version with related fix

Author: grey-rain

pom.xml

@@ -38,7 +38,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <serenity.version>4.0.8</serenity.version>
+        <serenity.version>4.0.21</serenity.version>
         <rp.client.version>5.1.22</rp.client.version>
         <rp.commons.version>5.8.1</rp.commons.version>
     </properties>