Update actions/checkout action to v6 (#40)

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

Author: renovate[bot]

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
@@ -53,10 +53,10 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: "Checkout build-cs"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: "phpstan/build-cs"
           path: "build-cs"
@@ -99,7 +99,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
@@ -133,7 +133,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: "Install PHP"
         uses: "shivammathur/setup-php@v2"
@@ -165,7 +165,7 @@ jobs:
 
     steps:
       - name: "Checkout"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - uses: ./.github/actions/setup-php
         with:

.github/workflows/tests.yml

@@ -56,13 +56,13 @@ jobs:
 
     steps:
       - name: "Checkout extension"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: "phpstan/${{ matrix.extension-name }}"
           fetch-depth: ${{ matrix.fetch-depth }}
 
       - name: "Checkout build-infection"
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: "build-infection"