Ubuntu 20.04 is EOL today

Author: hsbt

.github/workflows/build.yml

@@ -26,7 +26,6 @@ jobs:
         ubuntu_version:
           - noble
           - jammy
-          - focal
         dev_suffix: [ '', '-dev' ]
         debug_suffix: ['', '-debug']
         arch: ['amd64', 'arm64']
@@ -121,7 +120,6 @@ jobs:
         ubuntu_version:
           - noble
           - jammy
-          - focal
         image_version_suffix: [ '', '-dev', '-debug', '-debug-dev' ]
 
     runs-on: ubuntu-latest

.github/workflows/test.yml

@@ -14,7 +14,6 @@ jobs:
         ubuntu_version:
           - noble
           - jammy
-          - focal
         ruby_version:
           - 3.2.8
           - 3.3.7

README.md

@@ -53,23 +53,6 @@ The list of image names in this repository is below:
   - rubylang/ruby:3.1-jammy
   - rubylang/ruby:3.1.6-jammy
 
-### Ubuntu 20.04 (focal)
-
-- master
-  - rubylang/ruby:master-focal
-  - rubylang/ruby:master-dev-focal
-  - rubylang/ruby:master-debug-focal
-  - rubylang/ruby:master-debug-dev-focal
-- 3.3
-  - rubylang/ruby:3.3-focal
-  - rubylang/ruby:3.3.5-focal
-- 3.2
-  - rubylang/ruby:3.2-focal
-  - rubylang/ruby:3.2.5-focal
-- 3.1
-  - rubylang/ruby:3.1-focal
-  - rubylang/ruby:3.1.6-focal
-
 ### Misc
 
 We have some other images for special purposes.