[PATCH v2 0/3] Fix broken CI on newer github-actions runner image

[Jiang Xin <worldhello.net@gmail.com>]

From: Jiang Xin <zhiyou.jx@alibaba-inc.com>

GitHub CI runner image "ubuntu-latest" will upgrade to "ubuntu-22.04"
soon, and the CI runner image of my private host repository has
already been upgraded.

Our CI will break on new runner image because there is not "gcc-8"
package in ubuntu-22.04. See log of CI#2:

 * https://github.com/jiangxin/git-ci-test/actions/runs/3537628107/jobs/5937769957

This issue is fixed in patch 1/3 by downgrade the version of the runner
image for jobs which need "gcc-8". But there are still some CI errors.
This is because p4/p4d version 16.2 cannot run on ubuntu-22.04. See this
log of CI#3:

 * https://github.com/jiangxin/git-ci-test/actions/runs/3537650146/jobs/5937813922

This issue is fixed in patch 2/3 by upgrade p4 and p4d. But all p4
related test cases failed becasue python was missing on ubuntu-22.04.
See the log of CI#4:

 * https://github.com/jiangxin/git-ci-test/actions/runs/3537695959/jobs/5937929695

This issue is fixed in patch 3/3 by install python2/python3 on ubutnu.

If install p4 version 22.2, will break several p4 related test cases,
see the log of CI#7:

 * https://github.com/jiangxin/git-ci-test/actions/runs/3538795233/jobs/5939989823

So we choose p4 21.2, and the final successful log of CI#8 is below:

 * https://github.com/jiangxin/git-ci-test/actions/runs/3538946849

--
Jiang Xin (3):
  github-actions: run gcc-8 on ubuntu-20.04 image
  ci: upgrade version of p4 to 21.2
  ci: install python on ubuntu

 .github/workflows/main.yml | 16 ++++++++++++----
 ci/install-dependencies.sh | 12 ++++++------
 ci/lib.sh                  | 10 ++++++----
 3 files changed, 24 insertions(+), 14 deletions(-)

-- 
2.39.0.rc0