Merge pull request 'fix: update checkout action to use shared-actions version' (#12) from chore/checkout into main

Reviewed-on: #12
Reviewed-by: Markus.Opahle@schmalz.de <Markus.Opahle@schmalz.de>

.forgejo/workflows/validate-shared-actions.yml

@@ -12,7 +12,8 @@ jobs:
     runs-on: stackit-ubuntu-22
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: https://schmalz-git.git.onstackit.cloud/schmalz/shared-actions/checkout@checkout-v1
+
       - name: Validate shared action metadata
         uses: docker://data.forgejo.org/forgejo/runner:12
         with: