fix: use ubuntu-latest for npm publish (OIDC requires GitHub-hosted runners) (#24)

### TL;DR

Updated the runner for the npm publish workflow from a custom runner to the standard GitHub-hosted runner.

### What changed?

Changed the `runs-on` parameter in the npm-publish.yml workflow from `blacksmith-4vcpu-ubuntu-2404` to `ubuntu-latest`.

### How to test?

Trigger the npm publish workflow and verify that it runs successfully on the standard GitHub-hosted runner.

### Why make this change?

Testing to see if we must use Github's runners for automated trusted publishing to npm.

Author: ichoosetoaccept

.github/workflows/npm-publish.yml

@@ -12,7 +12,7 @@ permissions:
 jobs:
   publish:
     name: Publish to npm
-    runs-on: blacksmith-4vcpu-ubuntu-2404
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@v6