fix(auto-pr): Fix git status detection

- Reverts: https://github.com/lukesampson/scoop/pull/3026

See https://git-scm.com/docs/git-status#_short_format
If the file was modified it shows ` M` and `M ` means it's staged.
 Files only containing whitespaces don't get staged by `git add` and we only care about actually staged files.

Since the order of the `git status`-output is not sorted anymore the `Select-Object -First 1` is useless and it now uses `Where-Object` to find the correct line.

bin/auto-pr.ps1

@@ -185,8 +185,8 @@ hub diff --name-only | ForEach-Object {
 
         # detect if file was staged, because it's not when only LF or CRLF have changed
         $status = execute 'hub status --porcelain -uno'
-        $status = $status | Select-Object -First 1
-        if ($status -and $status -match "^\x20*M\x20+.*$app.json") {
+        $status = $status | Where-Object { $_ -match "M\s{2}.*$app.json" }
+        if ($status -and $status.StartsWith('M  ') -and $status.EndsWith("$app.json")) {
             execute "hub commit -m '${app}: Update to version $version'"
         } else {
             Write-Host "Skipping $app because only LF/CRLF changes were detected ..." -ForegroundColor Yellow