Update release-drafter config to support v7

[gaeljw]

The v7 of release-drafter introduces some breaking changes requiring changes in the config files stored here.

See docs: https://github.com/release-drafter/release-drafter/blob/master/docs/configuration-loading.md, mentionned in the changelog:

following the removal of probot, we replaced the Probot Config plugin with custom-made syntax and capabilities. Key takeaways are :

• fallback to your org/user .github repo does not work anymore. You will need to be explicit about it. (ex: config-name: .github:/configs/release-drafter/main.yaml)
• the _extends config-keyword now uses the same syntax as the config-name: input. Read more in the Configuration Loading article

See also failed/failing attempts at upgrading release-drafter:

• Bump release-drafter/release-drafter from 6 to 7 anorm#686 (comment) (I tried and reverted): Repo load failed. Config file not found with error 404. (target: playframework/.github:.github/release-drafts/.github/release-drafts/base.yml)
• https://github.com/playframework/playframework/actions/runs/23963814467 it's failing for a couple of weeks with Repo load failed. Config file not found with error 404. (target: playframework/.github:.github/.github/release-drafts/increasing-patch-version.yml)

In my understanding, at least 1 thing to fix in this repo is the reference in https://github.com/playframework/.github/blob/main/.github/release-drafts/increasing-minor-version.yml to _extends: .github:.github/release-drafts/base.yml which should be made absolute or relative to the increasing-minor-version.yml?

- _extends: .github:.github/release-drafts/base.yml
+ _extends: .github:/.github/release-drafts/base.yml 
or
+ _extends: .github:base.yml 

---

Then, some changes may also be required in downstream projects like:

• explicitly use this .github repo:

- config-name: release-drafts/increasing-minor-version.yml
+ config-name: .github:release-drafts/increasing-minor-version.yml

• do not specify the .github folder or use absolute path

- _extends: .github:.github/release-drafts/increasing-minor-version.yml
+ _extends: .github:release-drafts/increasing-minor-version.yml 
or 
+ _extends: .github:/.github/release-drafts/increasing-minor-version.yml

[mkurz]

Can you provide a PR for this repo? I can then take care of all the others.

[gaeljw]

I'll do that in the coming days. I'll see if I can have downstream repos reference a pending branch/PR, otherwise I may have to do a couple of PRs before I get this right (I doubt I get it to work at first try 😅)