Update buildkite plugin plugin-linter to v3.1.0

[renovate]

This PR contains the following updates:

Package	Update	Change
plugin-linter	minor	v3.0.0 -> v3.1.0

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Release Notes

buildkite-plugins/plugin-linter-buildkite-plugin

v3.1.0: (🥑 Guacamole)

Compare Source

Changed:

• Pin image to actual version (#​48) @​toote
• Update Linter image tag version (#​49) @​pzeballos

Upgrading

To upgrade, update your pipeline.yml files:

steps:
  - plugins:
-     plugin-linter#v3.0.0:
+     plugin-linter#v3.1.0:
        id: my-org/my-plugin

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Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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