reckon: 0.6.0 -> 0.7.1

Particularly nice improvements:
* [fail on unknown account](https://github.com/cantino/reckon/pull/102)
  in interactive mode
* [use - to read from stdin](https://github.com/cantino/reckon/pull/98)

pkgs/tools/text/reckon/default.nix

@@ -15,8 +15,10 @@ stdenv.mkDerivation rec {
       gemdir = ./.;
     };
   in ''
+    runHook preInstall
     mkdir -p $out/bin
     makeWrapper ${env}/bin/reckon $out/bin/reckon
+    runHook postInstall
   '';
 
   passthru.updateScript = bundlerUpdateScript "reckon";