fix(ci): skip auto-approve for github-actions[bot] authored PRs

GITHUB_TOKEN resolves to github-actions[bot], which cannot approve PRs
authored by the same identity (e.g., release-please PRs). Check the PR
author to skip the job entirely instead of failing.

Ref: #77
Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>

Author: SebTardif

.github/workflows/auto-approve.yml

@@ -20,8 +20,8 @@ jobs:
       contents: write
       pull-requests: write
     if: >-
-      github.actor == 'SebTardif' ||
-      github.actor == 'dependabot[bot]'
+      github.event.pull_request.user.login != 'github-actions[bot]' &&
+      (github.actor == 'SebTardif' || github.actor == 'dependabot[bot]')
     steps:
       - name: Harden runner
         uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0