Description of problem:

gem2rpm uses a previously deprecated uri-open api that has been removed from Ruby 3.0.

Version-Release number of selected component (if applicable):

rubygem-gem2rpm-1.0.1-7.fc34.noarch

How reproducible:

Always

Steps to Reproduce:
1. 

Run:

gem2rpm  --fetch something

"something" is non-existing gem, but it always fails when using --fetch

Actual results:

/usr/share/gems/gems/gem2rpm-1.0.1/bin/gem2rpm:55:in `initialize': No such file or directory @ rb_sysopen - https://rubygems.org/api/v1/gems/something.json (Errno::ENOENT)
	from /usr/share/gems/gems/gem2rpm-1.0.1/bin/gem2rpm:55:in `open'
	from /usr/share/gems/gems/gem2rpm-1.0.1/bin/gem2rpm:55:in `<top (required)>'
	from /usr/bin/gem2rpm:23:in `load'
	from /usr/bin/gem2rpm:23:in `<main>'

Expected results:

Gem fetch failed with error: 404 Not Found

Additional info:

The following change fixes the problem:

--- /usr/share/gems/gems/gem2rpm-1.0.1/bin/gem2rpm.orig	2021-04-24 08:29:46.075929560 +0200
+++ /usr/share/gems/gems/gem2rpm-1.0.1/bin/gem2rpm	2021-04-24 08:31:50.231335838 +0200
@@ -52,12 +52,12 @@
 if options[:fetch]
   gem_uri = ''
   begin
-    open("https://rubygems.org/api/v1/gems/#{gemfile}.json") do |f|
+    URI.open("https://rubygems.org/api/v1/gems/#{gemfile}.json") do |f|
       gem_uri = f.read.match(/"gem_uri":\s*"(.*?)",/m)[1]
       gemfile = URI.parse(gem_uri).path.split('/').last
       gemfile = File.join(out_dir, gemfile)
-      open(gemfile, 'w') do |gf|
-        gf.write(open(gem_uri).read)
+      URI.open(gemfile, 'w') do |gf|
+        gf.write(URI.open(gem_uri).read)
       end
     end
   rescue OpenURI::HTTPError => e