ci(windows): install hg for tests (#6993)

.github/workflows/workflow.yml

@@ -181,11 +181,17 @@ jobs:
           # cargo-wix does not require static crt
           RUSTFLAGS: ""
 
-      # Install Mercurial (pre-installed on Linux and windows)
+      # Install Mercurial (pre-installed on Linux)
       - name: Setup | Mercurial (macos)
         if: matrix.os == 'macOS-latest'
         run: brew install mercurial
 
+      - name: Setup | Mercurial (windows)
+        if: matrix.os == 'windows-latest'
+        run: |
+          winget install --id Mercurial.Mercurial --silent --exact --disable-interactivity --accept-source-agreements
+          Add-Content -Path $env:GITHUB_PATH -Value "C:\Program Files\Mercurial" -Encoding utf8
+
       # Run the ignored tests that expect the above setup
       - name: Build | Test
         run: "cargo llvm-cov