To do this you need to manually patch the stock boot image and flash that to your boot partition.
However, I've done all of this and with a few steps you'll be rooted.
There's a more detailed guide below.
1) Get bootloader unlock code here
2) Enable "OEM Unlocking", boot into fastboot and type: "fastboot oem unlock your-unlock-code"
3) Download patched ramdisk image here and put it in fastboot directory.
4) Reboot into fastboot and type: "fastboot flash ramdisk patched_ramdisk.img"
(Optional) 5) Flash this to go back to stock ramdisk
First off, you need an unlocked bootloader. To do this, you need a special code from Huawei, you can request this here:
With this code, and having "OEM unlocking" enabled in debugger settings, boot in fastboot mode.
Afterwards, open fastboot console and type: "fastboot oem unlock your-unlock-code"
Your device will now reboot.
Now reboot your device back into fastboot mode and open a fastboot console once more.
Download this patched ramdisk partition and place it in the same folder as your fastboot executable.
Now simply type in the console: "fastboot flash ramdisk patched_ramdisk.img".
Reboot your phone and it is rooted!
Download Magisk Manager to update/configure Magisk.
To remove the root, simply flash this original ramdisk partition, the same way as above. You can also relock the bootloader if wanted.