Run Maven build in release.sh concurrently to speedup release

Change-Id: Iad8696825bb81becab945cd9ed2c33bea3778e17
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

tools/release.sh

diff --git a/tools/release.sh b/tools/release.sh
index 7adb375..d180bdf 100755
--- a/tools/release.sh
+++ b/tools/release.sh
@@ -47,6 +47,5 @@
 git tag -sf -m "$MSG" $1
 
 # run the build
-mvn clean install
+mvn clean install -T 1C
 mvn clean install -f org.eclipse.jgit.packaging/pom.xml
-