Tools that opens PowerShell in Unity project's Git root folder.

PowerShellOpener.cs

using System.Diagnostics;
using UnityEditor;

public static class PowerShellOpener
{
    [MenuItem("Tools/PowerShell")]
    private static void NewMenuOption()
    {
        var process = new ProcessStartInfo("powershell.exe")
        {
            WindowStyle = ProcessWindowStyle.Maximized,
            Arguments = "-noexit git rev-parse --show-toplevel | cd"
        };
        Process.Start(process);
    }
}