workflows/bot: request read permissions for members

The nixpkgs-ci token used in CI doesn't have permissions to read the
member list of the nixpkgs-committers team, yet. Let's request this
permission and see whether that fixes the errors we get so far.

.github/workflows/bot.yml

@@ -60,8 +60,10 @@ jobs:
         with:
           app-id: ${{ vars.NIXPKGS_CI_APP_ID }}
           private-key: ${{ secrets.NIXPKGS_CI_APP_PRIVATE_KEY }}
+          permission-administration: read
           permission-contents: write
           permission-issues: write
+          permission-members: read
           permission-pull-requests: write
 
       - name: Log current API rate limits