Switch CI/CD to Github Actions?

[aktech]

I think @travis-ci is becoming annoying day by day, the last job triggered has been in the queue for over an hour and its mostly like this.

[oscarbenjamin]

Travis are slowly ramping down the number of jobs available to open source projects:
https://www.traviscistatus.com/#month

To be fair to them they are doing this gradually so that CI can still run while projects migrate. The ending is clear though: all projects need to migrate away from Travis.

The main sympy codebase (along with most other open source projects) has moved to Actions so it would make sense for sympy live to do the same.

[Abhishek-IOT]

@aktech @oscarbenjamin Jenkins can also be one of the options ...as it is free and open source also....but as codebase is moved to Actions we can do this also.