Log Message:
ruby-addressable: update to 2.8.4.

Upstream changes:
 https://github.com/sporkmonger/addressable/blob/addressable-2.8.4/CHANGELOG.md

 Addressable 2.8.4

  * Restore Addressable::IDNA.unicode_normalize_kc as a deprecated method
    (#504)

 Addressable 2.8.3

  * Fix template expand level 2 hash support for non-string objects (#499,
    #498)

 Addressable 2.8.2

  * Improve cache hits and JIT friendliness (#486)
  * Improve code style and test coverage (#482)
  * Ensure reset of deferred validation (#481)
  * Resolve normalization differences between IDNA::Native and IDNA::Pure
    (#408, #492)
  * Remove redundant colon in Addressable::URI::CharacterClasses::AUTHORITY
    regex (#438) (accidentally reverted by #449 merge but added back in #492)