Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/lint.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v4"
+        uses: "actions/checkout@v6"
 
       - name: Cache dependencies
         uses: actions/cache@v4

.github/workflows/phpstan.yml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: "actions/checkout@v4"
+        uses: "actions/checkout@v6"
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"

.github/workflows/security.yml

@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # This action checks the `composer.lock` file against known security vulnerabilities in the dependencies.
       # https://github.com/marketplace/actions/the-php-security-checker

.github/workflows/tests.yml

@@ -25,7 +25,7 @@ jobs:
     name: Tests PHP${{ matrix.php }} - ${{ matrix.os }} - ${{ matrix.dependency-version }} - monero ${{ matrix.monero }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Spin up containers
         run: docker compose -ftests/docker-compose.yml up -d
@@ -59,7 +59,7 @@ jobs:
     name: "Code coverage report"
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Spin up containers
         run: docker compose -f tests/docker-compose.yml up -d