Allow for "default" config to run if no path match

[fivetran-joseolmo]

Hi!
Would it be possible to have a “default” build for when no path matched the watched folders?
So, basically, we’d like to have a pipeline definition like this:

steps:
  - key: tests-pipeline
    label: ":pipeline:"
    plugins:
      - monorepo-diff#v1.0.1:
          watch:
            - path: folder_a/**
              config:
                command: buildkite-agent pipeline upload a_tests.yml
            - path: folder_b/**
              config:
                command: buildkite-agent pipeline upload b_tests.yml
            - default:
              config:
                command: buildkite-agent pipeline upload other_tests.yml

We want other_tests to run if the changes happen on any folder other than folder_a or folder_b
Also, like the current functionality on the plugin, if change happens on all three "paths" we would like all three pipelines to run.
We could accomplish this with glob exclude patterns but they do not seem to work at the moment according to this issue: adikari#95

[jamietanna]

This would probably cover the suggestion raised in #20 (comment) (aka else) quite nicely

[tomowatt]

Hey @fivetran-joseolmo
With the release of v1.1.0 which includes the support for a "default" config, wanted to check if this resolves this issue and the request?