ensure right code is checked out

Author: lorenzwalthert

.github/workflows/hook-dependencies-update.yml

@@ -32,6 +32,7 @@ jobs:
       - name: auto-release
         run: Rscript -e 'source("renv/activate.R"); renv::restore(); renv::install("."); precommit:::auto_release()' 
       - name: Create Pull Request
+        id: cpr
         uses: peter-evans/create-pull-request@v7.0.7
         with:
           token: ${{ secrets.PRECOMMIT_HOOK_DEPENDENCY_UPDATE }}
@@ -44,7 +45,13 @@ jobs:
             This PR updates the hook dependencies in `renv.lock`, auto-generated by [create-pull-request][1]. Close and re-open this to trigger `on: pull_request` events to circumvent [limitation of GitHub actions](https://github.com/peter-evans/create-pull-request/blob/master/docs/concepts-guidelines.md#push-pull-request-branches-to-a-fork).
 
             [1]: https://github.com/peter-evans/create-pull-request
-          
+      - name: Checkout PR head SHA
+        if: steps.cpr.outputs['pull-request-operation'] != 'none'
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ steps.cpr.outputs['pull-request-head-sha'] }}
+          fetch-depth: 0  # good practice if you need history
+
       - name: Push latest tag
         run: |
           Rscript -e "install.packages('desc')"