Add Buildkite CLI plugin

[micahbenn]

Overview

This PR adds a shell plugin for the Buildkite CLI: https://buildkite.com/docs/platform/cli.

Type of change

• Created a new plugin
• Improved an existing plugin
• Fixed a bug in an existing plugin
• Improved contributor utilities or experience

Related Issue(s)

• Resolves: N/A
• Relates: N/A

How To Test

Requirements

• Buildkite account: https://buildkite.com/signup (it's free)
• Buildkite API token: https://buildkite.com/user/api-access-tokens
• API token saved to 1Password with these fields:
  • organization: your_organization_slug (Buildkite > Settings)
  • token: your_api_token

Steps

1. Build the plugin locally: make buildkite/build
2. Initialize: op plugin init buildkite
3. Test authentication: bk whoami

Changelog

Authenticate the Buildkite CLI using Touch ID and other unlock options with 1Password Shell Plugins.

[micahbenn]

Hi @edif2008 @SimonBarendse, may I get some eyes on this please? Not sure who to ping for reviews but I saw you both approve a past PR. Thank you!