[Tooling] Automate changelog generation

[jaydeluca]

Right now as part of the release process, we run a few steps locally and have to do some manual work. It would be great to automate all of this so that we can kick off a github action that will generate the changelog, have it reviewed by copilot or equivalent to touch it up, and then present it for review by the release captain.

[jaydeluca]

this is the existing instrumentation scripts for reference:
https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/.github/scripts/draft-release-notes

[harshitt13]

@jaydeluca Thanks for linking those scripts! And @breedx-splk, I understand that we don't want to use chloggen. Porting this Python-based LLM pipeline from the main instrumentation repo seems like the perfect middle ground—it automates the release captain's job without forcing external contributors to change their workflow or write YAML.

Before I update my existing PR, I want to ensure the codeowners are fully on board with this specific approach. Here is my exact plan:

1. Revert: Gut the chloggen architecture from my draft PR.
2. Port Scripts: Copy the 5 files (fetch.py, classify.py, merge.py, draft-release-notes.py, and rules.md) into .github/scripts/draft-release-notes/.
3. Update Targets: Update the hardcoded repository references inside those scripts to point to open-telemetry/opentelemetry-java-contrib.
4. Add Workflow: Create a new .github/workflows/draft-release-notes.yml triggered via workflow_dispatch that sets up Python, installs the necessary CLIs (GitHub and Copilot), and executes the pipeline for the Release Captain.

@jack-berg @jaydeluca @breedx-splk Does this plan work for you? Please confirm this approach, and I'll push these updates to the PR.

[jaydeluca]

yes i think those are the right steps, we just need confirmation and coordination from @trask that we'll be able to add a copilot token for this task

[harshitt13]

@jaydeluca Sounds good! I will wait until @trask confirms the token availability. Thanks for the guidance.

[trask]

I added COPILOT_GITHUB_TOKEN under "protected" environment secret, see #2859

[harshitt13]

Thanks @trask !
I will start working and will push the changes shortly.

[harshitt13]

@jaydeluca @jack-berg @breedx-splk @trask
I have completely updated the PR (#2837), and it's ready for review whenever you have a moment.