Bump Nix

Dependencies

• [2] 34UH6B6L Build against the bleeding edge of Nix
• [3] 6K5PBUUN Use buildEnv to combine Hydra's Perl dependencies
• [4] DODOGD7M Send queue runner stats to statsd
• [*] T4LLYESZ * Nix expression for building Hydra.

Change contents

• replacement in release.nix at line 61
  [2.565]→[2.565:700](∅→∅)
  − rev = "b0f7f9c98f2b54e34e9344f817d30363533d108f";

  − sha256 = "1xwdlnbsdlsqplzv7s3gaiv1s8mb26qqy17gazl4hy1d3djp0hvl";
  [2.565]

  [2.700]
  + rev = "edf9eb8181e01f6b2123e5690019cfeeb44fc1c2";

  + sha256 = "1a00q9pypfziyi9hxl4rsammhwj7991wm4b1z9zcgl7zqksr3582";