Enable eSpeak-NG on Windows

[cclauss]

      - name: Download and install eSpeak-NG
        if: runner.os == 'Windows'
        shell: pwsh
        run: |
          Invoke-WebRequest -Uri "https://github.com/espeak-ng/espeak-ng/releases/download/1.51/espeak-ng-X64.msi" -OutFile "espeak-ng.msi"
          Start-Process msiexec.exe -ArgumentList '/i espeak-ng.msi /quiet /norestart' -Wait
          # dir "$env:ProgramFiles\eSpeak NG"
          $env:Path += ";$env:ProgramFiles\eSpeak NG"
          espeak-ng --version