Update environment settings for maven 3.3.1

For those who use 3.2.3 (as specified in Blackbird), here is the upgrade instruction.
cd ~/Downloads
wget https://www.apache.org/dist/maven/maven-3/3.3.1/binaries/apache-maven-3.3.1-bin.tar.gz
tar -zxvf apache-maven-3.3.1-bin.tar.gz -C ~/Applications/

Change-Id: I11d98faf1405e120fdff5748c5875c8842f4c58d
diff --git a/tools/dev/onos.cshrc b/tools/dev/onos.cshrc
index 53f8624..5dc3298 100644
--- a/tools/dev/onos.cshrc
+++ b/tools/dev/onos.cshrc
@@ -24,7 +24,7 @@
     endif
 endif
 if ( ! $?MAVEN ) then
-    setenv MAVEN $HOME/Applications/apache-maven-3.2.2
+    setenv MAVEN $HOME/Applications/apache-maven-3.3.1
 endif
 if ( ! $?KARAF_VERSION ) then
     setenv KARAF_VERSION 3.0.2