Update buildkite plugin docker-login to v3

[renovate]

This PR contains the following updates:

Package	Update	Change
docker-login	major	v2.1.0 -> v3.0.0

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Release Notes

buildkite-plugins/docker-login-buildkite-plugin (docker-login)

v3.0.0: (🎄 Christmas Shopping)

Compare Source

Added

• Logout rework (#​73) @​toote

Upgrading

To upgrade, update your pipeline.yml files:

steps:
  - plugins:
-     docker-login#v2.2.0:
+     docker-login#v3.0.0:
        username: myuser

v2.2.0: (🍝 Yummy Pasta)

Compare Source

Added

• Support password-env containing newlines (#​70) @​joemiller

Upgrading

To upgrade, update your pipeline.yml files:

steps:
  - plugins:
-     docker-login#v2.1.0:
+     docker-login#v2.2.0:
        username: myuser

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Configuration

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

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

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