Add Index Exchange to fledge-tester-list.md (#742)

SHA: 630e1ab
Reason: push, by JensenPaul

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

index.html

@@ -6,7 +6,7 @@
   <link href="https://www.w3.org/StyleSheets/TR/2021/cg-draft" rel="stylesheet">
   <meta content="Bikeshed version d29f71adb, updated Wed Jul 19 11:08:56 2023 -0700" name="generator">
   <link href="https://wicg.github.io/turtledove/" rel="canonical">
-  <meta content="95720603c49d4522adcf3437155823c46f7c788f" name="document-revision">
+  <meta content="630e1abeda08f36a48a541d9db2440c5c148fad1" name="document-revision">
 <style>
 /* domintro from https://resources.whatwg.org/standard.css */
 .domintro {