Update libraries to current versions

commons-io:commons-io ............................. 2.5 -> 2.6
org.assertj:assertj-core ...................... 3.8.0 -> 3.9.1

Author: stefanbirkner

pom.xml

@@ -9,7 +9,7 @@
     </parent>
 
     <artifactId>fake-sftp-server-rule</artifactId>
-    <version>2.0.0</version>
+    <version>2.1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>Fake SFTP Server Rule</name>
@@ -66,13 +66,13 @@
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
-            <version>[2.5]</version>
+            <version>[2.6]</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>[3.8.0]</version>
+            <version>[3.9.1]</version>
             <scope>test</scope>
         </dependency>
         <dependency>