Update README.md (Mozilla-Ocho#316)

Additional case for wsl Gotchas

README.md

@@ -307,6 +307,12 @@ On WSL, it's recommended that the WIN32 interop feature be disabled:
 sudo sh -c "echo -1 > /proc/sys/fs/binfmt_misc/WSLInterop"
 ```
 
+In the instance of getting a `Permission Denied` on disabling interop through CLI, it can be permanently disabled by adding the following in `/etc/wsl.conf`
+```sh
+[interop]
+enabled=false
+```
+
 On Raspberry Pi, if you get "mmap error 12" then it means your kernel is
 configured with fewer than 48 bits of address space. You need to upgrade
 to RPI 5. You can still use RPI 4 if you either (1) rebuild your kernel,