Update padding-spec.txt to cover hs circuit setup obfuscation

https://github.com/mikeperry-tor/torspec/tree/hs-padding-spec is the updated padding spec with the necessary changes. Current HEAD to merge is 479f0dc4bd2a873ab153ed0e7d7066e975069929

changed milestone to %Tor: 0.4.2.x-final

Trac:
Parent Ticket: #28804 (moved)

added 041-proposed component::core tor/tor milestone::Tor: 0.4.2.x-final network-team-roadmap-august padding parent::28804 priority::high resolution::implemented scalability-roadmap severity::normal status::closed tor-cell tor-relay tor-spec type::task wtf-pad labels

asn previously reviewed this in ticket:28804#comment:19. He said the spec update piece was good.

Trac:
Cc: nickm to nickm, asn
Status: new to merge_ready

Merged; thanks!

Trac:
Status: merge_ready to closed
Priority: Medium to High
Resolution: N/A to implemented
Milestone: Tor: unspecified to Tor: 0.4.2.x-final

closed

moved to tpo/core/tor#31806 (closed)