fix(client) allow semaphore wait in some ssl_* phases
fix(client) allow semaphore wait in some ssl_* phases

`ssl_cert` and `ssl_session_fetch` can both yield, but were missing from
the supported list. Without this, a client running in one of these
phases may fail to resolve unexpectedly.

https://github.com/Kong/lua-resty-dns-client/commit/e723618cd268b42ff51d36a5b3a1bec6e1b431f3

Kong/kong,Kong/kong,Kong/kong