[CI] Support ppc64le arch in Travis CI

[srinivas32]

Added power support for the travis.yml file with ppc64le. This is part of the Ubuntu distribution for ppc64le. This helps us simplify testing later when distributions are re-building and re-releasing. For more info tag @gerrith3.

[jiasli]

Our CI doesn't use Travis anymore, but uses Azure DevOps now.

We only tested on x86 machines. This will surely be a better-to-have feature, but we haven't got any chance to test it.

I will look into it. Thanks for the contribution.

[jiasli]

@srinivas32, do you have any chance to run the code in Travis with ppc64le?

[gerrith3]

@jiasli at the moment there is no ppc64le hardware in Azure. We do provide free access to ppc64le through OSL here: https://osuosl.org/services/powerdev/ and of course free access to ppc64le architecture in travis-ci.com for testing. We are looking into a golang github runner, but thus far we haven't gotten very far with bootstrapping .NET/.NET core on ppc64le which is otherwise necessary to connect to other coverage services. The best we can offer at the moment is GHA for x86/x86-64 and Travis for ppc64le, s390x, arm, macOS...

[jiasli]

I tested with on my own repo jiasli@44e9ac1.

The result shows ppc64le arch is working correctly:

https://travis-ci.com/github/jiasli/knack/builds/207397999

[haroldrandom]

@srinivas32 @gerrith3 We have disconnected Travis for a long time and no plan to bring it back for now. If you want to use Travis why not fork our repo, modify it as your request, and periodically sync with upstream?

[gerrith3]

@haroldrandom We'd rather avoid permanently forking a repo here. We'll try and reconnect when we have ppc64le connected to GHA.