Update CODEOWNERS for PR #1118 (#1132)

Add @joshjohanning as owner of agents/github-actions-node-upgrade.agent.md

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 3 people

CODEOWNERS

@@ -40,3 +40,6 @@
 /skills/codeql/ @VeVarunSharma
 /skills/dependabot/ @VeVarunSharma
 /skills/secret-scanning/ @VeVarunSharma
+
+# Added via #codeowner from PR #1118
+/agents/github-actions-node-upgrade.agent.md @joshjohanning