[CI] Update junit buildkite plugin

[mrodm]

Update Buildkite junit-annotate plugin up to version 2.7.0

Set run-in-docker: false to use the ruby from the agent.

[v1v]

Let's use the new docker image :)

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 630d8c3

History

• 💚 Build #5842 succeeded d2c91ae
• 💚 Build #5825 succeeded 2896a47
• 💚 Build #5820 succeeded 96ea4c6
• 💚 Build #5818 succeeded c939dd0
• 💔 Build #5817 failed 9776947
• 💔 Build #5816 failed 64b4b28

cc @mrodm