Add R library "dialr" to third party ports (#2586)

[dialr](https://github.com/socialresearchcentre/dialr/) is an R wrapper around the libphonenumber Java library (not a port as such)

README.md

@@ -227,6 +227,7 @@ maintenance processes.
 *   Rust: https://github.com/1aim/rust-phonenumber
 *   Erlang: https://github.com/marinakr/libphonenumber_erlang
 *   Clojure: https://github.com/randomseed-io/phone-number
+*   R: https://github.com/socialresearchcentre/dialr/
 
 Alternatives to our own versions: