ARROW-14816: [R] Implement bindings for lubridate::mday

[AlenkaF]

Adding a binding for lubridate::mday in expressions.R and a test for date and timestamp.

Note: day() is an aliase for mday() in lubridate.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-14816

[thisisnic]

Thanks!

[rok]

Would this be a candidate for another c++ kernel?

[thisisnic]

Would this be a candidate for another c++ kernel?

@rok From my understanding it is already using a C++ kernel - day.

[ursabot]

Benchmark runs are scheduled for baseline = 584b360 and contender = 3fa2d21. 3fa2d21 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.0% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.09% ⬆️0.04%] ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python. Runs only benchmarks with cloud = True
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[AlenkaF]

@rok yes, Nic is correct. Note that the binding for day or mday map to the same C++ function day as they are aliases in lubridate.

[rok]

Ah, sorry for the noise :)