Allow any yarn version in manifest
Allow any yarn version in manifest

[#141167599]

Signed-off-by: Dave Goddard <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@goddard.id.au>
ekaranto/rails4-bluemix-buildpack,ekaranto/rails4-bluemix-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,ekaranto/rails4-bluemix-buildpack,cloudfoundry/ruby-buildpack,ekaranto/rails4-bluemix-buildpack,cloudfoundry/ruby-buildpack