Re: [PATCH v4 1/4] github-actions: run gcc-8 on ubuntu-20.04 image

> From: Jiang Xin <zhiyou.jx@alibaba-inc.com>
>
> GitHub starts to upgrade its runner image "ubuntu-latest" from version
> "ubuntu-20.04" to version "ubuntu-22.04". It will fail to find and
> install "gcc-8" package on the new runner image.
>
> Change some of the runner images from "ubuntu-latest" to "ubuntu-20.04"
> in order to install "gcc-8" as a dependency.
>
> The first revision of this patch tried to replace "$runs_on_pool" in
> "ci/*.sh" with a new "$runs_on_os" environment variable based on the
> "os" filed in the matrix strategy. But these "os" fields in matrix

> strategies are obsolete legacies from commit [1] and commit [2], and
> are no longer useful. So remove these unused "os" fields.
>
> [1]: c08bb26010 (CI: rename the "Linux32" job to lower-case "linux32",
>                  2021-11-23)
> [2]: 25715419bf (CI: don't run "make test" twice in one job, 2021-11-23)
>
> Reviewed-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> ---