feat(dev-infra): add dev-infra to the commit message scopes (#35992)

Adds dev-infra to the commit message scopes.  Also, sets the scope to be ignored
in changelogs.

PR Close #35992

tools/gulp-tasks/changelog.js

@@ -10,6 +10,7 @@ module.exports = (gulp) => () => {
   const conventionalChangelog = require('gulp-conventional-changelog');
   const ignoredScopes = [
     'aio',
+    'dev-infra',
     'docs-infra',
     'zone.js',
   ];