download karaf 4.2.1 from maven central

Change-Id: Icb7e0400ee5b34ed4be33afdda5074a6f6ec1f6d
diff --git a/tools/dev/bash_profile b/tools/dev/bash_profile
index c4f54d0..7fcedad 100644
--- a/tools/dev/bash_profile
+++ b/tools/dev/bash_profile
@@ -22,7 +22,7 @@
 
 export MAVEN=${MAVEN:-~/Applications/apache-maven-3.3.9}
 
-export KARAF_VERSION=${KARAF_VERSION:-3.0.8}
+export KARAF_VERSION=4.2.1
 export KARAF_ROOT=${KARAF_ROOT:-~/Applications/apache-karaf-$KARAF_VERSION}
 export KARAF_LOG=$KARAF_ROOT/data/log/karaf.log