Travis-CI/publishing: our publishing stuff doesn't work on dist: bionic but generating spec PDF requires it

[SethTisue]

some gory details at #762

[dwijnand]

Move the dist to the language spec (Jekyll) job, leaving the other jobs (e.g. publishing) to use the default. Now the default might've also changed since Dec 2020, but it might fix it for you.

[SethTisue]

do you know for sure whether you're allowed to set dist: at the job level and not the build level?

[dwijnand]

I'm fairly sure because this example seems to suggest it:

https://docs.travis-ci.com/user/multi-os/#example-multi-os-build-matrix

jobs:
  include:
    - os: linux
      dist: trusty
    - os: osx
      osx_image: xcode7.2

seeing as you can define a matrix of not even linux, makes sense that the linux distribution is matrixable.

[SethTisue]

nice. okay, trying it here: scala/scala#9516

[SethTisue]

This appears to be working. This seems satisfactory for now, actually. Xenial will likely remain available for a while yet to come on Travis-CI. If they ever drop it, or if we move to GitHub Actions, we might need to figure out something else, but it seems like a bridge we can cross when we come to it.