Use Github Actions for CI

[JaeyeongYang]

I found that travis-ci.org is ceased since June 15th, 2021, and it might be better to find one to replace it for continuous integration. One good candidate is Github Actions, which provides an automative workflow integrated with the Github repository.

[MarkAPitt]

I have used CodeShip and found it reliable. Use whatever is most convenient.
Hope you are well, Jaeyeong.

[JaeyeongYang]

Hi Mark, thanks for the suggestion!

As you mentioned, CodeShip seems reliable and worthy to try. For now, however, I feel GitHub Actions is the easiest option for integrating with the repository, but I will consider CodeShip as an option, just in case.

I hope you are well, too! :)