Exclude two more flaky GitHub URLs from markdown link check

The lychee pre-push hook was returning cached 502s for two CHANGELOG.md
links. Mirror the existing pattern in this file by excluding both, so
unrelated markdown link flakiness doesn't block branch pushes.

- #785
- https://github.com/K4sku

Author: justin808

.lychee.toml

@@ -113,6 +113,7 @@ exclude = [
   '^https://github\.com/shakacode/react_on_rails/compare/',
   '^https://github\.com/shakacode/react_on_rails/pull/[0-9]+$',  # Intermittent 5xx from GitHub PR pages in CI
   '^https://github\.com/shakacode/shakapacker/blob/cdf32835d3e0949952b8b4b53063807f714f9b24/package/environments/base\.js(#.*)?$',  # Intermittent 502 from GitHub blob view in CI
+  '^https://github\.com/K4sku$',  # Intermittent 502 from GitHub user page in CI
 
   # ============================================================================
   # DELETED GITHUB USER ACCOUNTS (return 502/404 from CI)