Drop Ubuntu 20.10 container, it's EOL

Author: mpe

README.md

@@ -58,7 +58,6 @@ There are images for various toolchains, they are encoded in the distro name/ver
  - kernel.org gcc 5.5.0 `korg@5.5.0`
  - Ubuntu 21.10 `ubuntu@21.10`
  - Ubuntu 21.04 `ubuntu@21.04`
- - Ubuntu 20.10 `ubuntu@20.10`
  - Ubuntu 20.04 `ubuntu@20.04`
  - Ubuntu 18.04 `ubuntu@18.04`
  - Ubuntu 16.04 `ubuntu@16.04`

build/Makefile

@@ -58,7 +58,7 @@ DOCS += docs@${1}@${2}
 endef
 
 FEDORA_DISTROS := fedora@35 fedora@34 fedora@33 fedora@31
-UBUNTU_DISTROS := ubuntu@21.10 ubuntu@21.04 ubuntu@20.10 ubuntu@20.04 ubuntu@18.04 ubuntu@16.04
+UBUNTU_DISTROS := ubuntu@21.10 ubuntu@21.04 ubuntu@20.04 ubuntu@18.04 ubuntu@16.04
 KORG_DISTROS := korg@11.1.0 korg@10.3.0 korg@9.3.0 korg@8.1.0 korg@5.5.0
 ALL_DISTROS := ${UBUNTU_DISTROS} ${KORG_DISTROS} ${FEDORA_DISTROS}
 DOCS_DISTRO := docs@21.10