github actions: remove ubuntu 18.04; add ubuntu 22.04

Author: ra1nb0w

.github/workflows/ci.yml

@@ -63,26 +63,26 @@ jobs:
               cmake_extra_flags: ''
             }
           - {
-              name: 'Ubuntu 20.04',
-              os: ubuntu-20.04,
+              name: 'Ubuntu 22.04',
+              os: ubuntu-22.04,
               cc: 'gcc',
               cxx: 'g++',
               arch: 'x86_64',
               build_type: 'Release',
               cmake_extra_flags: ''
             }
           - {
-              name: 'Ubuntu 18.04',
-              os: ubuntu-18.04,
+              name: 'Ubuntu 20.04',
+              os: ubuntu-20.04,
               cc: 'gcc',
               cxx: 'g++',
               arch: 'x86_64',
               build_type: 'Release',
               cmake_extra_flags: ''
             }
           - {
-              name: 'Ubuntu 16.04',
-              os: ubuntu-16.04,
+              name: 'Ubuntu 18.04',
+              os: ubuntu-18.04,
               cc: 'gcc',
               cxx: 'g++',
               arch: 'x86_64',