macOS: add backups dir to the sample launchd service

init/com.github.drakkan.sftpgo.plist

@@ -14,6 +14,8 @@
         <string>/usr/local/opt/sftpgo/templates</string>
         <key>SFTPGO_HTTPD__STATIC_FILES_PATH</key>
         <string>/usr/local/opt/sftpgo/static</string>
+        <key>SFTPGO_HTTPD__BACKUPS_PATH</key>
+        <string>/usr/local/opt/sftpgo/backups</string>
     </dict>
     <key>WorkingDirectory</key>
     <string>/usr/local/opt/sftpgo/etc</string>
@@ -27,4 +29,4 @@
     <key>ThrottleInterval</key>
     <integer>10</integer>
 </dict>
-</plist>
+</plist>