.travis.yml: Upgrade the Ubuntu ppc64le to 22.04 (Jammy).
Seeing the recent successes on RubyCI ppc64le Ubuntu jammy servers, it's time to upgrade Travis ppc64le to jammy.
http://rubyci.s3.amazonaws.com/ppc64le/ruby-master/recent.html
Upgrade the gcc version to the latest version 11.4.0 to align the gcc version used in the RubyCI ppc64le server's gcc version.
.travis.yml: Upgrade the Ubuntu ppc64le to 22.04 (Jammy).
Seeing the recent successes on RubyCI ppc64le Ubuntu jammy servers, it's time
to upgrade Travis ppc64le to jammy.
http://rubyci.s3.amazonaws.com/ppc64le/ruby-master/recent.html
Upgrade the gcc version to the latest version 11.4.0 to align the gcc
version used in the RubyCI ppc64le server's gcc version.