[i18n-activity] Subscription request needs to define UTF-8

aphillips has just created a new issue for 
https://github.com/w3c/i18n-activity:

== Subscription request needs to define UTF-8 ==
https://w3c.github.io/websub/#subscriber-sends-subscription-request

In section 5.1, the subscription request is defined:

> Subscription is initiated by the subscriber making an HTTPS or HTTP 
POST [RFC7231] request to the hub URL. This request MUST have a 
Content-Type header of application/x-www-form-urlencoded (described in
 Section 17.13.4 of [W3C.REC-html401-19991224]) and the following 
parameters in its body, formatted accordingly:

URL Encoded does not define the character encoding used. Normally, the
 encoding is inferred from the sending page/URL. The specification 
should define the encoding explicitly to always be UTF-8.

Please view or discuss this issue at 
https://github.com/w3c/i18n-activity/issues/324 using your GitHub 
account