Use extra-binary-caches

Dependencies

• [2] HZWUT4YN Allow users to reproduce builds on their own systems
• [3] 3G7OYUSE reproduce.tt: Check for the presence of commands like nix-build
• [4] TL7KZWSU reproduce.tt: Use color

Change contents

• replacement in src/root/reproduce.tt at line 165
  [2.3276]→[2.3276:3331](∅→∅)
  − #args+=(--option binary-caches '[% c.uri_for('/') %]')
  [2.3276]

  [2.3331]
  + args+=(--option extra-binary-caches '[% c.uri_for('/') %]')