fix(renovate): add ct-changesets[bot] to gitIgnoredAuthors (#3300)

The renovate-changeset workflow commits via the CT Changesets GitHub
App (ct-changesets[bot]). Without this entry, Renovate flags those
commits as external edits and blocks auto-rebase.

Author: ByronDWall

.github/renovate.json

@@ -5,7 +5,8 @@
   ],
   "rebaseWhen": "never",
   "gitIgnoredAuthors": [
-    "41898282+github-actions[bot]@users.noreply.github.com"
+    "41898282+github-actions[bot]@users.noreply.github.com",
+    "145970804+ct-changesets[bot]@users.noreply.github.com"
   ],
   "packageRules": [
     {