chore: upgrade actions/checkout to version 5 in workflow files

- Updated the actions/checkout version from v4 to v5 in fix-php-code-styling.yml, phpstan.yml, run-tests.yml, and update-changelog.yml workflows.

Author: chrisreedio

.github/workflows/fix-php-code-styling.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           ref: ${{ github.head_ref }}
 

.github/workflows/phpstan.yml

@@ -11,7 +11,7 @@ jobs:
     name: phpstan
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2

.github/workflows/run-tests.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2

.github/workflows/update-changelog.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           ref: 3.x