🐛 ci(renovate): fix OOM crash and stop using Mend's default gitAuthor

The 2026-07-03 runs surfaced two config problems:

- The grouped "renovate/all" branch made Renovate fetch and hold the
  changelog of every upgrade instance separately (Traefik v3.0.0->v3.7.6
  was fetched ~10x, once per compose file), which blew the default 4GB
  V8 heap: "FATAL ERROR: ... JavaScript heap out of memory" (exit 134),
  killing the run after the branch was pushed but before the PR was
  opened. Disable changelog fetching (release notes were truncated in
  the grouped PR body anyway) and raise the Node heap to 8GB as a
  safety net.

- No gitAuthor was set, so commits were authored as Mend's
  renovate@whitesourcesoftware.com, which GitHub flags "Unverified"
  (Vigilant Mode) and Renovate warns about on every run. Use the token
  owner's noreply address instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/renovate.yml

@@ -35,4 +35,7 @@ jobs:
           RENOVATE_REPOSITORIES: ${{ github.repository }}
           RENOVATE_ONBOARDING: "false"
           RENOVATE_REQUIRE_CONFIG: "required"
+          # The grouped "all" branch holds many upgrades; changelog/PR-body
+          # rendering for it blew the default 4GB V8 heap (exit 134 OOM).
+          NODE_OPTIONS: "--max-old-space-size=8192"
           LOG_LEVEL: ${{ github.event.inputs.logLevel || 'info' }}

renovate.json

@@ -1,6 +1,8 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": ["config:recommended"],
+  "gitAuthor": "Renovate Bot <22881669+maxlerebourg@users.noreply.github.com>",
+  "fetchChangeLogs": "off",
   "labels": ["dependencies"],
   "ignorePaths": ["**/vendor/**", "**/node_modules/**"],
   "rangeStrategy": "bump",