ruby-backports: new upstream version 3.3.5 (fix FTBFS #720249)

[David Suárez <david.sephirot@gmail.com>]

Hi,

I have updated ruby-backports to a new upstream version.

Some comments:
  * Fix collision with hash function (Closes: #720249)
  * Bump standards version to 3.9.5; no changes needed
  * Add build-depend on ruby-activesupport to run specs

It builds fine on a sid chroot.

Can anyone review and upload it.

Thanks,
  David