Upgrade update-winget action to v1.4

This version allows us to update existing `winget` manifests by
specifying a manifest's SHA if it already exists in `microsoft/winget-pkgs`.

Pull Requests
---------------

* [git-for-windows#178](mjcheetham/update-winget#179): Allow
updates to existing winget manifests

Author: ldennington

.github/workflows/release-winget.yml

@@ -9,7 +9,7 @@ jobs:
     steps:
     - id: update-winget
       name: Update winget repository
-      uses: mjcheetham/update-winget@v1.3.2
+      uses: mjcheetham/update-winget@v1.4
       with:
         id: Microsoft.Git
         token: ${{ secrets.WINGET_TOKEN }}