(maint) Add rubocop exclusion

Rubocop is triggering on a valid ssl_version

lib/pdk/util/vendored_file.rb

@@ -51,7 +51,7 @@ def download_file
         uri = URI.parse(url)
         http = Net::HTTP.new(uri.host, uri.port)
         http.use_ssl = true
-        http.ssl_version = :TLSv1_2
+        http.ssl_version = :TLSv1_2 # rubocop:disable Naming/VariableNumber
         http.ca_file = @config['ssl-ca-cert']
         http.cert = OpenSSL::X509::Certificate.new(ssl_cert)
         http.key = OpenSSL::PKey::RSA.new(ssl_key)