Update actions/checkout action to v6

.gitea/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     container:
       image: registry.bobert.me/anthorob/coder-base:terraform
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Terraform validate for each template
         run: |
@@ -38,7 +38,7 @@ jobs:
       COMMIT_SHORT_SHA: ${{ github.sha }}
       REPO: ${{ github.repository }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Deploy each template
         run: |