fixup! Add a GitHub workflow to verify that Git/Scalar work in Nano Server

Bump actions/checkout from v5 to v6 and
git-for-windows/setup-git-for-windows-sdk from v1 to v2.

Both bumps are Node.js 20 to Node.js 24 runtime migrations with
no functional changes to the actions themselves. checkout v6 moves
persisted credentials to `` instead of `.git/config`,
which does not affect this workflow since no subsequent steps rely
on the credential location. The setup-sdk v2 provisions the same
minimal SDK as v1.

Risk: very low. The only precondition is a recent Actions Runner,
which github.com-hosted runners already satisfy.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.github/workflows/nano-server.yml

@@ -14,8 +14,8 @@ jobs:
       IMAGE: mcr.microsoft.com/powershell:nanoserver-ltsc2022
 
     steps:
-      - uses: actions/checkout@v5
-      - uses: git-for-windows/setup-git-for-windows-sdk@v1
+      - uses: actions/checkout@v6
+      - uses: git-for-windows/setup-git-for-windows-sdk@v2
       - name: build Git
         shell: bash
         run: make -j15