Update stale.yml to use old version as a bug fix

There is a well-documented issue w/ the new actions/stale version (v9.0.0) that causes the following error: "Error delete _state: [403] Resource not accessible by integration". See actions/stale#1133 for more context.

There are two potential fixes if we continue to use the new version: (1) run the action on all PRs/issues to avoid using the cache or (2) give write access to the endpoints listed in https://docs.github.com/en/rest/authentication/permissions-required-for-fine-grained-personal-access-tokens?apiVersion=2022-11-28#repository-permissions-for-actions. Neither of these options is preferable, so I am going to wait until the bug is fixed.

Note: The old version (v8.0.0) uses Node 16, which will be deprecated in Spring 2024, instead of Node 20, so we should keep an eye on this issue.

.github/workflows/stale.yml

@@ -13,7 +13,7 @@ jobs:
       issues: write
       pull-requests: write
     steps:
-      - uses: actions/stale@v9.0.0
+      - uses: actions/stale@v8
         with:
           # Comma separated list of labels that can be assigned to issues to exclude them from being marked as stale
           exempt-issue-labels: contributions welcome, feature request, regression