:construction_worker: build ci_module_cpp20 with MSVC

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/windows.yml

diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index cf0833b..c4b97cc 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -115,6 +115,7 @@
   ci_module_cpp20:
     runs-on: windows-latest
     steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Run CMake (Debug)
         run: cmake -S . -B build -G "Visual Studio 17 2022" -DJSON_CI=ON -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8 /W4 /WX"
       - name: Build