Update actions/checkout action to v4

| datasource  | package          | from | to |
| ----------- | ---------------- | ---- | -- |
| github-tags | actions/checkout | v3   | v4 |


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

Author: renovate[bot]

.github/workflows/backward-compatibility-check.yml

@@ -22,7 +22,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 

.github/workflows/coding-standard.yml

@@ -26,7 +26,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Install PHP"
               uses: "shivammathur/setup-php@2.30.2"

.github/workflows/integration.yml

@@ -27,7 +27,7 @@ jobs:
 
       steps:
         - name: "Checkout"
-          uses: actions/checkout@v3
+          uses: actions/checkout@v4
 
         - name: "Install PHP"
           uses: "shivammathur/setup-php@2.30.2"

.github/workflows/mutation-tests.yml

@@ -26,7 +26,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Install PHP"
               uses: "shivammathur/setup-php@2.30.2"

.github/workflows/phpstan.yml

@@ -26,7 +26,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Install PHP"
               uses: "shivammathur/setup-php@2.30.2"

.github/workflows/psalm.yml

@@ -26,7 +26,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Install PHP"
               uses: "shivammathur/setup-php@2.30.2"

.github/workflows/release-on-milestone-closed-triggering-release-event.yml

@@ -18,7 +18,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Release"
               uses: "laminas/automatic-releases@v1"

.github/workflows/unit.yml

@@ -36,7 +36,7 @@ jobs:
 
         steps:
             - name: "Checkout"
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: "Install PHP"
               uses: "shivammathur/setup-php@2.30.2"