update commons dependencies (#15)

diff --git a/pom.xml b/pom.xml
index 3909d7c..cff44df 100644
--- a/pom.xml
+++ b/pom.xml
@@ -248,9 +248,9 @@
 
     <!-- commons -->
     <dependency>
-      <groupId>commons-collections</groupId>
-      <artifactId>commons-collections</artifactId>
-      <version>3.2.1</version>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-collections4</artifactId>
+      <version>4.2</version>
     </dependency>
     <dependency>
       <groupId>commons-httpclient</groupId>
@@ -260,17 +260,17 @@
     <dependency>
       <groupId>commons-io</groupId>
       <artifactId>commons-io</artifactId>
-      <version>2.5</version>
+      <version>2.6</version>
     </dependency>
     <dependency>
-      <groupId>commons-lang</groupId>
-      <artifactId>commons-lang</artifactId>
-      <version>2.6</version>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-lang3</artifactId>
+      <version>3.8.1</version>
     </dependency>
     <dependency>
       <groupId>commons-logging</groupId>
       <artifactId>commons-logging</artifactId>
-      <version>1.1.1</version>
+      <version>1.2</version>
     </dependency>
 
     <!-- doxia -->