RUBYGEMS_FORCE_DISABLE_GEM_SIGNING=true disable key signing for rb-sy…

…s gem build. (#379)

* RUBYGEMS_FORCE_DISABLE_GEM_SIGNING=true disable key signing for rb-sys gem build.

* Fix rubocops

---------

Co-authored-by: Ian Ker-Seymer <i.kerseymer@gmail.com>

gem/rb_sys.gemspec

@@ -23,7 +23,9 @@ Gem::Specification.new do |spec|
 
   # Security
   spec.cert_chain = ["certs/ianks.pem"]
-  spec.signing_key = File.expand_path("~/.ssh/gem-private_key.pem") if $0.end_with?("gem")
+  unless ENV["RUBYGEMS_FORCE_DISABLE_GEM_SIGNING"] == "true"
+    spec.signing_key = File.expand_path("~/.ssh/gem-private_key.pem") if $0.end_with?("gem")
+  end
 
   spec.metadata["rubygems_mfa_required"] = "true"
 end