feat: upgrade go agent to v2

[kruskall]

What does this PR do?

go.elastic.co/apm v1 has been deprecated for a while. Update the dependency to v2.

Why is it important?

Checklist

• [ ] My code follows the style guidelines of this project
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have made corresponding change to the default configuration files
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have run the Unit tests (make unit-test), and they are passing locally
• [ ] I have run the End-2-End tests for the suite I'm working on, and they are passing locally
• [ ] I have noticed new Go dependencies (run make notice in the proper directory)

Author's Checklist

• [ ]

How to test this PR locally

Related issues

[mergify[bot]]

This pull request does not have a backport label. Could you fix it @kruskall? 🙏 To fixup this pull request, you need to add the backport labels for the needed branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 7./d branch. /d is the digit NOTE: backport-skip has been added to this pull request.