Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/ci-linux.yml

@@ -17,7 +17,7 @@ jobs:
       image: swift:${{ matrix.swift }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
 
       - name: APT cache
         uses: actions/[email protected]

.github/workflows/ci-macos.yml

@@ -15,7 +15,7 @@ jobs:
         xcode: ["14.1", "15.0"]
     steps:
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
 
       - name: Select Xcode ${{ matrix.xcode }}
         run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
@@ -73,7 +73,7 @@ jobs:
         xcode: ["13.4.1"]
     steps:
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
 
       - name: Select Xcode ${{ matrix.xcode }}
         run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app

.github/workflows/ci-windows.yml

@@ -17,7 +17,7 @@ jobs:
           tag: 5.8-RELEASE
 
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
 
       - name: Cache vcpkg
         uses: actions/[email protected]