README: updated the addresses to sr-dev and sr-users mailing lists

(cherry picked from commit dd3a55d190cf00066cb23a13d9c81827f1da14cd)

README

@@ -106,7 +106,7 @@ To receive feedback to your inquiries, we recommend you to subscribe
 to the sr-users mailing list and post your queries there. This mailing
 list is set up for mutual help by the community of Kamailio users and developers.
 To participate in the mailing list, subscribe at the following web address:
-         https://lists.sip-router.org/mailman/listinfo/sr-users
+         https://lists.kamailio.org/mailman/listinfo/sr-users
 
 The IRC channel #kamailio on freenode.net is a place where to meet and discuss
 with other members of Kamailio community.

README.md

@@ -83,11 +83,11 @@ To report a bug or make a request for new features, use the Issues Page in the K
 
 Mailing list for discussions regarding stable versions of Kamailio:
 
-  * **sr-users (at) lists.sip-router.org** - [sr-users web page](https://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users)
+  * **sr-users (at) lists.kamailio.org** - [sr-users web page](https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users)
 
 Mailing list for discussions regarding the development of Kamailio and the state of master (devel) branch:
 
-  * **sr-dev (at) lists.sip-router.org** - [sr-dev web page](https://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev)
+  * **sr-dev (at) lists.kamailio.org** - [sr-dev web page](https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-dev)
 
 Mailing list for discussions with commercial purpose: