Fix typo - Update README.md

[PallHaraldsson]

[skip ci]

[PallHaraldsson]

Windows (default filesystem) is case-insensitive, as you may so I assume aliases are too (for consistency):

https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/new-alias?view=powershell-7.4

I only see actually editbin or EDITBIN.EXE, not the mixed-case I used. signtool.exe is probably what you see in file-system but I also see SignTool.exe is some Microsoft docs.