CI: Set up CI for ARM

[datapythonista]

xref #33971

This used to run in Travis, but seems like Travis now requires credits, and we can't get them reliably (see #38943).

This page contains CI systems that support ARM. Most of them require to set up our own runner, which I guess we don't want to do or maintain. So, the main options seem to be:

• drone.io
• CircleCI

CC: @bashtage

[jreback]

there are multiple issue about this already

we got a renewal of travis credits but it's not enough

drone.io is not designed for a big ci like we need

circle is a possibility

cc @fangchenli

[datapythonista]

Thanks for the extra info. Based on the discussion in #38943 seems like Travis is not a reliable option. It took several months to get credits, and they lasted less than a week. I don't think there is any other issue about setting up an ARM build if the problem can't be solved with Travis, that's why I opened this one. Let me know if I'm missing anything.

[datapythonista]

CC: @cphang99

[fangchenli]

Just for reference. We have tried drone.io in #39742.

[simonjayhawkins]

drone is used for the conda packages and run times seam reasonable (around half an hour) (compared to the ppc build on azure, nearer 2 hours) https://cloud.drone.io/conda-forge/pandas-feedstock/115