Adding powershell 7 or higher requirement note to README.MD [skip ci]

README.MD

@@ -1,16 +1,21 @@
 # Valthrun UEFI mapper
+
 Automatically map the Valthrun driver from the UEFI.  
-Doing this has several advantages:  
+Doing this has several advantages:
+
 1. The Valthrun driver can be loaded before any other drivers
 2. You can create a bootable USB stick containing the latest Valthrun driver
 
 ## Build the ISO
+
 ```ps1
+# Requirements PowerShell 7 or higher.
 cargo b --target x86_64-unknown-uefi && .\scripts\Create-ISO.ps1 -Destination ./bootloader.iso
 ```
 
 ## Load the valthrun driver
+
 The valthrun driver should be automatically loaded when booting using the valthrun bootloader.  
 To use the bootloader create a bootable USB stick and boot from that.  
 On success you should see the following message:  
-![image](./media/screenshot_mapped_successfully.png)
+![image](./media/screenshot_mapped_successfully.png)