Add exempt-issue-labels to the issue triage GH Action job (#936)

Like I did for the TypeScript SDK project (see
openai/openai-agents-js#97), we may want to have
the labels to exclude the issues from auto-closing. Some of the issues
that have been open for a while could just need time.

Author: gold-crow-997

.github/workflows/issues.yml

@@ -21,6 +21,7 @@ jobs:
           days-before-pr-stale: 10
           days-before-pr-close: 7
           stale-pr-label: "stale"
+          exempt-issue-labels: "skip-stale"
           stale-pr-message: "This PR is stale because it has been open for 10 days with no activity."
           close-pr-message: "This PR was closed because it has been inactive for 7 days since being marked as stale."
           repo-token: ${{ secrets.GITHUB_TOKEN }}