Merge pull request #344 from chris18890/master

remove cosmic

src/ubuntu.ipxe

@@ -11,7 +11,6 @@ clear ubuntu_version
 menu ${os} - ${arch_a} - Image Sig Checks: [${img_sigs_enabled}]
 item --gap Latest Releases
 item disco ${space} ${os} 19.04 Disco Dingo
-item cosmic ${space} ${os} 18.10 Cosmic Cuttlefish
 item bionic ${space} ${os} 18.04 LTS Bionic Beaver
 item xenial ${space} ${os} 16.04 LTS Xenial Xerus
 item --gap Older Releases