phpPackages.composer: fix build (#498393)

  # use together with the version from this package to keep the

  # bootstrap phar file up-to-date together with the end user composer

  # package.

  passthru.pharHash = "sha256-Oz+VA6LUZZAXDkXt0pc0GX55fOpUWzltCygjysjvRkM=";

  passthru.pharHash = "sha256-yGzmA/6Da/CGGjjJOsVmyPHmmsRLJEXZt6ahfqLplyo=";

  meta = {

    changelog = "https://github.com/composer/composer/releases/tag/${finalAttrs.version}";