Request to reformat ping url

[phanduynam]

https://developer.wordpress.org/advanced-administration/wordpress/update-services/#xml-rpc-ping-services

Requires reformatting of ping url as below:
https://rpc.pingomatic.com/
https://rpc.twingly.com/
http://ping.blo.gs/

[kittenkamala]

Thanks! If you like, you can open a PR for this. (Just fork and clone the repo, make changes locally, commit and push to GitHub, and open a PR from there)