updated actions/checkout to v4

see https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/

Author: firewave

.github/workflows/CI-unixish.yml

@@ -17,7 +17,7 @@ jobs:
       CXX: ${{ matrix.compiler }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Install missing software on ubuntu
       if: matrix.os == 'ubuntu-22.04'

.github/workflows/CI-windows.yml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup msbuild.exe
         uses: microsoft/setup-msbuild@v1.1

.github/workflows/clang-tidy.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-22.04
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install missing software
         run: |