Update actions/checkout action to v6

.gitea/workflows/ci.yml

@@ -12,9 +12,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: hashicorp/setup-terraform@v4
+      - uses: hashicorp/setup-terraform@v3
 
       - name: fmt check — 1-nixos-node
         run: terraform fmt -check -recursive
@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Nomad CLI
         run: |
@@ -60,7 +60,7 @@ jobs:
     if: github.event_name == 'pull_request'
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0