pin the Node 24 action-releaser release

Problem

The v0.2.8 Releaser run completed but GitHub annotated stacksjs/action-releaser@v1.2.9 because that release targets the deprecated Node 20 action runtime. The upstream action already provides Node 24 in v1.2.11.

Scope

• Pin the Releaser workflow to the exact v1.2.11 commit.
• Publish a patch and verify the release workflow completes without the Node 20 annotation.

Evidence

• Annotated run: https://github.com/stacksjs/bumpx/actions/runs/29889752165
• Upstream tag: https://github.com/stacksjs/action-releaser/releases/tag/v1.2.11

Resolved by 6e5c830 and verified in the clean v0.2.9 Releaser run, which completed on the Node 24 action without the prior deprecation annotation: https://github.com/stacksjs/bumpx/actions/runs/29889857891