ci: migrate to GitHub actions (backport #720)

[mergify]

longhorn/longhorn#8039, longhorn/longhorn#8504

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This is an automatic backport of pull request #720 done by Mergify.

Including following PRs:

• ci: migrate to GitHub actions #720
• ci: only run push image for master branch #727

[mergify]

Cherry-pick of 1cc836f has failed:

On branch mergify/bp/v1.6.x/pr-720
Your branch is up to date with 'origin/v1.6.x'.

You are currently cherry-picking commit 1cc836f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: .drone.yml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally