update from https://github.com/Kozea/Radicale/issues/740

contrib/nginx/radicale.conf

@@ -2,6 +2,10 @@
 ###
 ### Usual configuration file location: /etc/nginx/default.d/
 
+## "well-known" redirect at least for Apple devices
+rewrite ^/.well-known/carddav /radicale/ redirect;
+rewrite ^/.well-known/caldav /radicale/ redirect;
+
 ## Base URI: /radicale/
 location /radicale/ {
     proxy_pass        http://localhost:5232/;