approved-for-ci-run.yml: use token to checkout the repo (#5266)

## Problem

Another thing I overlooked regarding'approved-for-ci-run`:
- When we create a PR, the action is associated with @vipvap and this
triggers the pipeline — this is good.
- When we update the PR by force-pushing to the branch, the action is
associated with @github-actions, which doesn't trigger a pipeline — this
is bad.

Initially spotted in #5239 / #5211
([link](https://github.com/neondatabase/neon/actions/runs/6122249456/job/16633919558?pr=5239))
— `check-permissions` should not fail.


## Summary of changes
- Use `CI_ACCESS_TOKEN` to check out the repo (I expect this token will
be reused in the following `git push`)

.github/workflows/approved-for-ci-run.yml

@@ -54,6 +54,7 @@ jobs:
       - uses: actions/checkout@v3
         with:
           ref: main
+          token: ${{ secrets.CI_ACCESS_TOKEN }}
 
       - run: gh pr checkout "${PR_NUMBER}"