0.17.0

Synced to flipcash2-protobuf-api@3bb442d3,
picking up #134. Only chat.v1
moved.

Added

• Group descriptions, up to 160 characters and moderated like the title.
  • chat.v1.Metadata.description (= 16).
  • Set at creation through description on PublicGroupChatParameters (= 4) and
    PrivateGroupChatParameters (= 3). Optional; empty sets none.
  • Changed through EditChatRequest.description (= 4), a Description { value } wrapper: unset
    leaves the description alone, and a set wrapper with an empty value clears it.
  • Announced as MetadataUpdate.DescriptionChanged (= 6, new_description).
• DESCRIPTION_MODERATED on StartChatResponse.Result (= 6) and EditChatResponse.Result (= 5).
  The response's flagged_category is set for it, as it is for TITLE_MODERATED.

Upgrading

Nothing existing changed: no renames, and no field or enum renumbering. Both new result cases come
after the existing ones. A client that ignores description keeps working, but one with an
exhaustive MetadataUpdate switch needs a DescriptionChanged case.