Update jnr dependencies

* jnr-ffi to 2.2.17
* jnr-posix to 3.1.20
* jnr-enxio to 0.32.18

pom.xml

@@ -59,7 +59,7 @@
     <dependency>
       <groupId>com.github.jnr</groupId>
       <artifactId>jnr-ffi</artifactId>
-      <version>2.2.16</version>
+      <version>2.2.17</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
@@ -71,13 +71,13 @@
     <dependency>
       <groupId>com.github.jnr</groupId>
       <artifactId>jnr-enxio</artifactId>
-      <version>0.32.17</version>
+      <version>0.32.18</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
       <groupId>com.github.jnr</groupId>
       <artifactId>jnr-posix</artifactId>
-      <version>3.1.19</version>
+      <version>3.1.20</version>
       <scope>compile</scope>
     </dependency>
   </dependencies>