chore: set ubuntu runner to ubuntu-22.04

This prevents an error when running puppeteer/chrome on latest Ubuntu

See:

- https://github.com/sinonjs/sinon/actions/runs/12502499977/job/34881594651?pr=2631

- puppeteer/puppeteer#13365

.github/workflows/main.yml

@@ -65,7 +65,7 @@ jobs:
           npm run unimported
 
   browser-test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4