[SPARK-33156][INFRA] Upgrade GithubAction image from 18.04 to 20.04

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to upgrade Github Action runner image from Ubuntu 18.04 (LTS) to Ubuntu 20.04 (LTS).

Why are the changes needed?

ubuntu-latest in GitHub Action is still Ubuntu 18.04 (LTS).

• https://github.com/actions/virtual-environments#available-environments

This upgrade will help Apache Spark 3.1+ preparation for vote and release on the latest OS.

This is tested here.

• https://github.com/dongjoon-hyun/spark/pull/36

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Pass the Github Action in this PR.

[SparkQA]

Test build #129812 has finished for PR 30050 at commit 8a154db.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

Seems like ubuntu-20.04 is a preview one and that's why ubuntu-latest doesn't point this out (I read actions/runner-images#1430 and https://docs.github.com/en/free-pro-team@latest/actions/reference/specifications-for-github-hosted-runners#supported-runners-and-hardware-resources).

Should we just maybe leave it as is so GitHub Actions will updates it in their side? In this way, we could avoid updating this version later when another Ubuntu comes out.

[dongjoon-hyun]

The reason why they are still there officially is that they couldn't verify that how many plugins (or actions) in their market place fail to support it.

However, it's not true for us. I verified that Apache Spark don't use none of the problematic actions in dongjoon-hyun#36 .

And, ubuntu_20.04 is LTS. I don't think we need to upgrade this until next LTS (22.04). It's almost two years.

[AmplabJenkins]

Test FAILed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder-K8s/34417/
Test FAILed.

[HyukjinKwon]

Okay, I don't have a strong opinion here. cc @maropu or @srowen

[maropu]

nit: how about leaving comments about the next LTS of ubuntu-20.04 here?

[maropu]

IMO latest was a bit ambiguous, so the new one (ubuntu-20.04) can make it easier to understand in which environment we run tests. Thanks, @dongjoon-hyun !

[maropu]

Seems fine to me

[dongjoon-hyun]

Thank you, @maropu . Sure!

[dongjoon-hyun]

Today, Scala Repo is extremely unstable. I saw the failure in all CIs.

Error:  https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0/0.15.0/jars/sbt-assembly.jar: download error: Caught java.io.IOException: Server returned HTTP response code: 504 for URL: https://dl.bintray.com/sbt/sbt-plugin-releases/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0/0.15.0/jars/sbt-assembly.jar (Server returned HTTP response code: 504 for URL: https://dl.bintray.com/sbt/sbt-plugin-releases/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0/0.15.0/jars/sbt-assembly.jar) while downloading https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/com.eed3si9n/sbt-assembly/scala_2.12/sbt_1.0/0.15.0/jars/sbt-assembly.jar

[dongjoon-hyun]

Github Action already passed in the previous commit and the last one is only adding comment. I'll merge this.
Thank you so much, @HyukjinKwon and @maropu !
Merged to master.