add gzip encoding header for sgvz files

See also https://github.com/hholzgra/ocitysmap/issues/36

support/apache-maposmatic-template

@@ -25,10 +25,11 @@
           Order allow,deny
           Allow from all
         </Directory>
+        AddEncoding gzip svgz
 
         LogLevel warn
         ServerSignature On
 
         CustomLog /path/to/maposmatic/logs/access.log combined
         ErrorLog /path/to/maposmatic/logs/error.log
-</VirtualHost>
+</VirtualHost>