GitHub Actions: update to checkout@v4

We seem to be getting "Node.js 16 actions are deprecated." warnings
for jobs that use checkout@v3.  Except for the i686 containers job
that is kept at checkout@v1 [*], update to checkout@v4, which is
said to use Node.js 20.

[*] 6cf4d90 (ci(main): upgrade actions/checkout to v3, 2022-12-05)
    refers to actions/runner#2115 and
    explains why container jobs are kept at checkout@v1.  We may
    want to check the current status of the issue and move it to the
    same version as other jobs, but that is outside the scope of
    this step.

Backported-from: e94dec0 (GitHub Actions: update to checkout@v4, 2024-02-02)
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: gitster

.github/workflows/check-whitespace.yml

@@ -19,7 +19,7 @@ jobs:
   check-whitespace:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
 

.github/workflows/main.yml

@@ -95,7 +95,7 @@ jobs:
       group: windows-build-${{ github.ref }}
       cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: git-for-windows/setup-git-for-windows-sdk@v1
     - name: build
       shell: bash
@@ -156,10 +156,10 @@ jobs:
       group: vs-build-${{ github.ref }}
       cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: git-for-windows/setup-git-for-windows-sdk@v1
     - name: initialize vcpkg
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: 'microsoft/vcpkg'
         path: 'compat/vcbuild/vcpkg'
@@ -286,7 +286,7 @@ jobs:
       runs_on_pool: ${{matrix.vector.pool}}
     runs-on: ${{matrix.vector.pool}}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - run: ci/install-dependencies.sh
     - run: ci/run-build-and-tests.sh
     - run: ci/print-test-failures.sh
@@ -319,7 +319,7 @@ jobs:
     runs-on: ubuntu-latest
     container: ${{matrix.vector.image}}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       if: matrix.vector.jobname != 'linux32'
     - uses: actions/checkout@v1
       if: matrix.vector.jobname == 'linux32'
@@ -349,7 +349,7 @@ jobs:
       group: static-analysis-${{ github.ref }}
       cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - run: ci/install-dependencies.sh
     - run: ci/run-static-analysis.sh
     - run: ci/check-directional-formatting.bash
@@ -372,7 +372,7 @@ jobs:
         artifact: sparse-20.04
     - name: Install the current `sparse` package
       run: sudo dpkg -i sparse-20.04/sparse_*.deb
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install other dependencies
       run: ci/install-dependencies.sh
     - run: make sparse
@@ -387,6 +387,6 @@ jobs:
       jobname: Documentation
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - run: ci/install-dependencies.sh
     - run: ci/test-documentation.sh