Try extracting GPG key.

templates/packagebuild.xml

@@ -46,6 +46,7 @@ git clone {{ UPSTREAM_URL }} upstream;
 export VERSION="$(head -1 {{ NAME }}/debian/changelog | sed -n '/(/,/)/{:a; $!N; /)/!{$!ba}; s/.*(\([^)]*\)).*/\1/p}' | cut -d '-' -f1)+git$(date +'%Y%m%d%H%M')";
 sed -i "1i{{ NAME }} ($VERSION-0ubuntu1~ppa1) {{ RELEASE }}; urgency=low\n\n  * CI upload.\n\n –– Lugito <info@lubuntu.me>  $(date +'%a, %d %b %Y %T %z')\n" {{ NAME }}/debian/changelog
 cat {{ NAME }}/debian/changelog
+tar xvf $GPG_KEY
       </command>
     </hudson.tasks.Shell>
   </builders>