Please note that we've upgraded the version of npm used in the Wikimedia continuous integration infrastructure. This means that CI should be more consistent with developers' local set-ups, and lets us test in a more normal environment. This change will only affect node-based CI tasks, like the standard eslint/stylelint/jsonlint/banana tasks.
This is a breaking change for npm, as it will no longer silently install peer dependencies – you need to specify them manually. If your repo was previously warning about peer dependencies, it may now no longer work, though we think we've fixed these. If you have this situation, you can fix it by adding the appropriate peer dependencies to your repo's package.json file, and if you can't work out how to fix it feel free to ask me or others in IRC; #wikimedia-releng is normally best.
Thanks all!