[rubygems/rubygems] Append a newline to the checksum file

https://github.com/rubygems/rubygems/commit/48ea2778e9

lib/bundler/gem_helper.rb

@@ -109,7 +109,7 @@ module Bundler
       require "digest/sha2"
       checksum = ::Digest::SHA512.file(built_gem_path).hexdigest
       target = File.join(base, "checksums", file_name)
-      File.write(target, checksum)
+      File.write(target, checksum + "\n")
       Bundler.ui.confirm "#{name} #{version} checksum written to checksums/#{file_name}."
     end
 

spec/bundler/bundler/gem_helper_spec.rb

@@ -172,7 +172,7 @@ RSpec.describe Bundler::GemHelper do
       it "calculates SHA512 of the content" do
         subject.build_checksum(Pathname(IO::NULL))
         sha_path = app_path.join("checksums", "#{File.basename(IO::NULL)}.sha512")
-        expect(File.read(sha_path)).to eql(Digest::SHA512.hexdigest(""))
+        expect(File.read(sha_path).chomp).to eql(Digest::SHA512.hexdigest(""))
       end
 
       context "when build was successful" do