Don't test on Ubuntu 14.04 (#183)
Don't test on Ubuntu 14.04 (#183)

Ubuntu 14.04 is about to be end-of-life and Bazel CI will stop supporting it shortly afterwards.

Context: https://groups.google.com/d/msg/bazel-dev/_D6XzfNkQQE/8TNKiNmsCAAJ
bazelbuild/rules_python,bazelbuild/rules_python,bazelbuild/rules_python