fix: add type:ignore for kubernetes imports in all files

mypy attr-defined errors on 'from kubernetes import config/client'
in request_upgrades.py and web.py — same fix already applied to
check_versions.py.

web.py

@@ -19,7 +19,7 @@ from datetime import datetime, timezone
 from fastapi import BackgroundTasks, FastAPI, Request
 from fastapi.responses import HTMLResponse, JSONResponse
 from fastapi.templating import Jinja2Templates
-from kubernetes import client, config
+from kubernetes import client, config  # type: ignore[attr-defined]
 from packaging.version import InvalidVersion, Version
 
 from check_versions import get_latest_version, parse_image_ref