ci(gemfile): allow rubygems proxy to be provided as an env var [skip ci]

noelmcloughlin · myii · commit 155747346c5b · 2022-01-26T08:41:55.000Z
* Automated using myii/ssf-formula#408
diff --git a/Gemfile b/Gemfile
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-source 'https://rubygems.org'
+source ENV['PROXY_RUBYGEMSORG'] || 'https://rubygems.org'
 
 # Install the `inspec` gem using `git` because versions after `4.22.22`
 # suppress diff output; this version fixes this for our uses.
