build: cleanup workflow

.github/workflows/build.yml

@@ -17,9 +17,6 @@ jobs:
           - { pkg: g++, exe: 'g++', version: 10 }
           - { pkg: g++, exe: 'g++', version: 11 }
           - { pkg: g++, exe: 'g++', version: 12 }
-          - { pkg: g++, exe: 'g++', version: 13 }
-          - { pkg: clang, exe: 'clang++', version: 8 }
-          - { pkg: clang, exe: 'clang++', version: 9 }
           - { pkg: clang, exe: 'clang++', version: 10 }
           - { pkg: clang, exe: 'clang++', version: 11 }
           - { pkg: clang, exe: 'clang++', version: 12 }
@@ -33,22 +30,16 @@ jobs:
             compiler: { pkg: g++, exe: 'g++', version: 8 }
           - os: ubuntu-latest
             compiler: { pkg: g++, exe: 'g++', version: 9 }
-          - os: ubuntu-latest
-            compiler: { pkg: clang, exe: 'clang++', version: 8 }
-          - os: ubuntu-latest
-            compiler: { pkg: clang, exe: 'clang++', version: 9 }
-          - os: ubuntu-latest
-            compiler: { pkg: clang, exe: 'clang++', version: 10 }
-          - os: ubuntu-latest
-            compiler: { pkg: clang, exe: 'clang++', version: 11 }
           - os: ubuntu-20.04
             compiler: { pkg: g++, exe: 'g++', version: 10 }
           - os: ubuntu-20.04
             compiler: { pkg: g++, exe: 'g++', version: 11 }
           - os: ubuntu-20.04
             compiler: { pkg: g++, exe: 'g++', version: 12 }
-          - os: ubuntu-20.04
-            compiler: { pkg: g++, exe: 'g++', version: 13 }
+          - os: ubuntu-latest
+            compiler: { pkg: clang, exe: 'clang++', version: 10 }
+          - os: ubuntu-latest
+            compiler: { pkg: clang, exe: 'clang++', version: 11 }
           - os: ubuntu-20.04
             compiler: { pkg: clang, exe: 'clang++', version: 12 }
           - os: ubuntu-20.04