Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

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

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

@@ -6,7 +6,7 @@ jobs:
     name: Backward compatibility check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: fetch tags
         run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*

.github/workflows/php-cs-fixer.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       -   name: Checkout code
-          uses: actions/checkout@v3
+          uses: actions/checkout@v4
 
       -   name: Fix style
           uses: docker://oskarstark/php-cs-fixer-ga

.github/workflows/psalm.yml

@@ -12,7 +12,7 @@ jobs:
     name: psalm
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2

.github/workflows/run-tests.yml

@@ -31,7 +31,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2

.github/workflows/update-changelog.yml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           ref: main