[make_wheel.yml] Also build wheels with ubuntu-20.04 (glibc 2.31)

Author: jagapiou

.github/workflows/make_wheel.yml

@@ -41,7 +41,8 @@ jobs:
     strategy:
       matrix:
         cfg:
-          - { name: 'Linux LLVM+libstdc++', os: 'ubuntu-22.04', cc: clang, cxx: clang++, config: --linkopt=-fuse-ld=lld }
+          - { name: 'ManyLinux 2.35 LLVM+libstdc++', os: 'ubuntu-22.04', cc: clang, cxx: clang++, config: --linkopt=-fuse-ld=lld }
+          - { name: 'ManyLinux 2.31 LLVM+libstdc++', os: 'ubuntu-20.04', cc: clang, cxx: clang++, config: --linkopt=-fuse-ld=lld }
           - { name: 'MacOS 11 x86_64 LLVM+libc++', os: 'macos-11', cc: clang, cxx: clang++, config: --config=libc++ --config=macos }
           - { name: 'MacOS 12 x86_64 LLVM+libc++', os: 'macos-12', cc: clang, cxx: clang++, config: --config=libc++ --config=macos }
           - { name: 'MacOS 13 x86_64 LLVM+libc++', os: 'macos-13', cc: clang, cxx: clang++, config: --config=libc++ --config=macos }