Update actions/checkout action to v6

| datasource  | package          | from | to |
| ----------- | ---------------- | ---- | -- |
| github-tags | actions/checkout | v5   | v6 |


Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/format_php.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 7
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}
 

.github/workflows/psalm.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}
 

.github/workflows/test.yml

@@ -33,7 +33,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v5"
+        uses: "actions/checkout@v6"
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"

.github/workflows/validator.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}