.github/zephyr: de-hardcode the remote name in the Windows build too

Fixes commit 4bc6488 (".github/zephyr: de-hardcode the name of the
zephyr remote")

(Yay for duplication)

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

.github/workflows/zephyr.yml

@@ -308,7 +308,7 @@ jobs:
           # Get some tags to fix `git describe`, see build-linux comments above.
           cd zephyr
           $_rev = "$(git rev-parse HEAD)"
-          git fetch --filter=tree:0 zephyrproject "${_rev}:_branch_placeholder"
+          git fetch --filter=tree:0 "$(git ls-remote --get-url)" "${_rev}:_branch_placeholder"
           git branch -D _branch_placeholder