Update README file with URLs.

Point to this modules official Git repository, and where dependencies
can be found.

README

 This is a Puppet module for configuring networking on hosts.
-Copyright © 2008-2019 its various authors.
+Copyright © 2008-2020 its various authors.
 
 
 ===== LICENSING =====
@@ -17,3 +17,20 @@ GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public
 License along with this module.
 If not, see <http://www.gnu.org/licenses/>.
+
+
+
+===== DEPENDENCIES =====
+
+This module depends on these other Puppet modules:
+
+- cfgfile
+  Can be found at https://gitlab.liu.se/NSC/puppetmodules/cfgfile.git.
+
+
+
+===== OFFICIAL SOURCE =====
+
+The official Git repository for this module is located at
+https://gitlab.liu.se/NSC/puppetmodules/networking.  Clone
+from https://gitlab.liu.se/NSC/puppetmodules/networking.git.