Update actions/checkout to v6

Author: mathbunnyru

{{cookiecutter.stack_name}}/.github/workflows/docker.yml

@@ -44,7 +44,7 @@ jobs:
 
     steps:
       - name: Checkout Repo ⚡️
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Set Up Python 🐍
         uses: actions/setup-python@v6