Remove macOS builds from Travis CI

[yasiribmcon]

This PR removes macOS build jobs from Travis CI as macOS builds are no longer supported in Travis CI.
Note : I am contributing my new code of the whole pull request, including one or several files that are either new files or modified ones, under the BSD-new license.

[lawrinn]

Thank you for your PR, but unfortunately I am not gonna merge it since we are moving to github actions for testing(as you may notice even in this PR automatic checks) and will stop to use travis. I am actually already supposed to remove all bindings with travis

[lawrinn]

Especially it is pity since you are a very rare contributor who gives license note in the PR comment without request :)

[yasiribmcon]

@lawrinn We now have hosted GitHub Actions runners available for the s390x (IBM Z) architecture. These runners are gradually being onboarded by open source communities, and we’d be happy to work with MariaDB ODBC Connector to enable CI for s390x builds using this setup. An onboarding document is available.

Please let me know your thoughts. Thanks!

[lawrinn]

Thanks, we will definitely consider this. Technically MariaDB does not support connectors on s390x, but we did run tests in Travis - your colleagues contributed PR for that and bug fixes on that platform. So, maybe we will continue doing this now on github actions.

[yasiribmcon]

Thanks for considering this!
We’ll be happy to help with the enablement.