[SPARK-30674][INFRA] Use python3 in dev/lint-python

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to use python3 instead of python in dev/lint-python.

Why are the changes needed?

Currently, dev/lint-python fails at Python 2. And, Python 2 is EOL since January 1st 2020.

$ python -V
Python 2.7.17

$ dev/lint-python
starting python compilation test...
Python compilation failed with the following errors:
Compiling ./python/setup.py ...
  File "./python/setup.py", line 27
    file=sys.stderr)
        ^
SyntaxError: invalid syntax

Does this PR introduce any user-facing change?

No. This is a dev environment.

How was this patch tested?

Jenkins is running this with Python 3 already.
The following is a manual test.

$ python -V
Python 3.8.0

$ dev/lint-python
starting python compilation test...
python compilation succeeded.

[dongjoon-hyun]

Hi, @HyukjinKwon . How do you think about this?

[dongjoon-hyun]

Also, cc @viirya . Could you review this PR?

[viirya]

hmm, so we currently fail to run dev/lint-python in Jenkins?

[dongjoon-hyun]

No~ Jenkins is using Python3. So, it's okay for now. This is for the other environments which python is pointing python2.
It's described in the PR description test section.

[SparkQA]

Test build #117546 has finished for PR 27394 at commit 1e2f50a.

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

[SparkQA]

Test build #117548 has finished for PR 27394 at commit 02e08a2.

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

[dongjoon-hyun]

Thank you, @HyukjinKwon and @viirya .

[dongjoon-hyun]

Retest this please

[SparkQA]

Test build #117552 has finished for PR 27394 at commit 02e08a2.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[dongjoon-hyun]

Merged to master.