Add signing cert for releases and fix url (karafka#323)

Author: mensfeld

certs/cert_chain.pem

@@ -0,0 +1,26 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

rdkafka.gemspec

@@ -8,7 +8,6 @@ Gem::Specification.new do |gem|
   gem.description = "Modern Kafka client library for Ruby based on librdkafka"
   gem.summary = "The rdkafka gem is a modern Kafka client library for Ruby based on librdkafka. It wraps the production-ready C client using the ffi gem and targets Kafka 1.0+ and Ruby 2.4+."
   gem.license = 'MIT'
-  gem.homepage = 'https://github.com/thijsc/rdkafka-ruby'
 
   gem.files = `git ls-files`.split($\)
   gem.executables = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
@@ -18,6 +17,11 @@ Gem::Specification.new do |gem|
   gem.version = Rdkafka::VERSION
   gem.required_ruby_version = '>= 2.7'
   gem.extensions = %w(ext/Rakefile)
+  gem.cert_chain = %w[certs/cert_chain.pem]
+
+  if $PROGRAM_NAME.end_with?('gem')
+    gem.signing_key = File.expand_path('~/.ssh/gem-private_key.pem')
+  end
 
   gem.add_dependency 'ffi', '~> 1.15'
   gem.add_dependency 'mini_portile2', '~> 2.6'