set mount-path

Change-Id: I601062a9b743baa5542d508edb18220b181d4c74
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>

.github/workflows/win.yml

@@ -32,6 +32,7 @@ jobs:
         workspace-copy: true
         drive-path: C:\\dev_disk.vhdx
         mount-if-exists: true
+        mount-path: "E:"
 
     - name: Check restored cache
       shell: pwsh