CI: Bump actions/checkout@v6

Author: jschueller

.github/workflows/build.yml

@@ -4,7 +4,7 @@ jobs:
   linux:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Build
         run: |
           sudo apt-get update -y && sudo apt-get install python3-dev python3-numpy guile-3.0-dev octave-dev cmake gfortran g++-mingw-w64-x86-64 gfortran-mingw-w64-x86-64
@@ -20,7 +20,7 @@ jobs:
   macos:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Build
         run: |
           brew install swig guile
@@ -31,8 +31,8 @@ jobs:
   windows:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v6
+      - uses: actions/setup-python@v6
         with:
           python-version: '3.12'
       - name: Build