Makes dump_commits_since.ps1 work on PowerShell 5.1 (#7680)

Tools/dump_commits_since.ps1

@@ -13,9 +13,12 @@ param(
 
 $r = @()
 
+$page = 1
+
 $qParams = @{
     "since" = $since.ToString("o");
     "per_page" = 100
+    "page" = $page
 }
 
 if ($until -ne $null) {
@@ -24,11 +27,19 @@ if ($until -ne $null) {
 
 $url = "https://api.github.com/repos/{0}/commits" -f $repo
 
+
+
 while ($null -ne $url)
 {
-    $resp = Invoke-WebRequest $url -Body $qParams
+    $resp = Invoke-WebRequest $url -UseBasicParsing -Body $qParams
 
-    $url = $resp.RelationLink.next
+    if($resp.Content.Length -eq 2) {
+        break
+    }
+
+    $page += 1
+    $qParams["page"] = $page
+    
 
     $j = ConvertFrom-Json $resp.Content
     $r += $j