Try an older version of the checkout action

Fix #53.

Author: gcapes

.github/workflows/release.yml

@@ -29,7 +29,7 @@ jobs:
     outputs:
       new_tag_name: ${{ steps.get_new_tag.outputs.new_tag_name }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0 # get all history and tags
           ref: ${{ github.event.pull_request.base.ref }}
@@ -152,7 +152,7 @@ jobs:
     needs: [bump-version]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
         with:
           ref: ${{ github.event.pull_request.base.ref }} # otherwise we get the ref when the workflow started (missing above commit)