Use Git 2.49.0 release candidate in test-fixtures-windows

This is to work around #1849, while still running tests and fixture
scripts that rely on Git being able to rename symlinks on Windows.

Author: EliahKagan

.github/workflows/ci.yml

@@ -165,6 +165,35 @@ jobs:
     runs-on: windows-latest
 
     steps:
+      - name: Upgrade Git for Windows to latest (pre)release
+        # This upgrades Git to work around https://github.com/GitoxideLabs/gitoxide/issues/1849.
+        # TODO: Remove this step once the runner image has Git 2.49.0 or higher.
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          $workingDir = '~/git-dl'
+          $repo = 'git-for-windows/git'
+          $pattern = 'Git-*-64-bit.exe'
+          $log = 'setup-log.txt'
+          # Inno Setup args reference: https://jrsoftware.org/ishelp/index.php?topic=setupcmdline
+          $arguments = @(
+              '/VERYSILENT',
+              '/SUPPRESSMSGBOXES',
+              '/ALLUSERS',
+              "/LOG=$log",
+              '/NORESTART',
+              '/CLOSEAPPLICATIONS',
+              '/FORCECLOSEAPPLICATIONS'
+          )
+
+          mkdir $workingDir | Out-Null
+          cd $workingDir
+          $newestTag = gh release list --repo $repo --limit 1 --json tagName --jq '.[0].tagName'
+          gh release download $newestTag --repo $repo --pattern $pattern
+          $installer = Get-Item $pattern
+          Start-Process -FilePath $installer -ArgumentList $arguments -NoNewWindow -Wait
+          Get-Content -Path $log -Tail 50
+          git version
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2