Set Maintainer field to Sipwise Development Team

From: Michael Prokop <mprokop@sipwise.com>

debian/control

@@ -1,7 +1,7 @@
 Source: ngcp-asterisk
 Section: comm
 Priority: extra
-Maintainer: Jon Bonilla <jbonilla@sipwise.com>
+Maintainer: Sipwise Development Team <support@sipwise.com>
 Build-Depends: debhelper (>= 7), autotools-dev, libssl-dev, libncurses-dev, libltdl-dev, unixodbc-dev
 Standards-Version: 3.7.3