bundled cacert.pem with --ssl-ca-file PATH option (#480)

* Add a bundled cacert.pem from curl's website
* Using the --ssl-ca-file PATH option overrides ENV var SSL_CA_PATH
* Having none of those allow you to use the default, the bundled cacert.pem
* Octokit's SSL config uses this new setting
* Rake task to update_ssl_ca_file
* Rubocop target 2.2

Rakefile

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 require "bundler"
 require "bundler/gem_tasks"
 require "rubocop/rake_task"
@@ -10,31 +11,10 @@ require "overcommit"
 RuboCop::RakeTask.new
 RSpec::Core::RakeTask.new(:rspec)
 
-task :copy_man_page_to_manpath do |_t|
-  known_manpath_paths = %w(/etc/manpath.config /etc/manpaths)
-  manpath = known_manpath_paths.find do |f|
-    path = Pathname(f)
-    path.file? && path.readable?
-  end
-
-  next unless manpath
-
-  writable_man_path = Pathname(manpath).each_line.find do |line|
-    path = Pathname(line.chomp)
-    path.directory? && path.writable?
-  end
-
-  next unless writable_man_path
-
-  man_prefix = Pathname("#{writable_man_path.chomp}/man1")
-  man_pages = "man/git-*.1"
-
-  Pathname.glob(man_pages) do |path|
-    if path.exist? && man_prefix.exist? && man_prefix.writable?
-      FileUtils.cp(path, man_prefix + path.basename)
-    end
-  end
+desc "When releasing the gem, re-fetch latest cacert.pem from curl.haxx.se. Developer task."
+task :update_ssl_ca_file do
+  `pushd lib/github_changelog_generator/ssl_certs && curl --remote-name --time-cond cacert.pem https://curl.haxx.se/ca/cacert.pem && popd`
 end
 
-task checks: [:rubocop, :rspec]
-task default: [:rubocop, :rspec]
+task checks: %i[rubocop rspec]
+task default: %i[rubocop rspec]