Give tests and examples separate ruff configs (#158)

This allows more fine-grained lint rule adjustments, and allows
the examples to treat fastapi_cache as a 'third party' module, just
like users of the library would use it.

examples/redis/main.py

@@ -2,20 +2,20 @@
 import time
 
 import pendulum
-import redis.asyncio as redis
 import uvicorn
 from fastapi import FastAPI
 from fastapi.responses import HTMLResponse
 from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
-from redis.asyncio.connection import ConnectionPool
-from starlette.requests import Request
-from starlette.responses import JSONResponse, Response
-
 from fastapi_cache import FastAPICache
 from fastapi_cache.backends.redis import RedisBackend
 from fastapi_cache.coder import PickleCoder
 from fastapi_cache.decorator import cache
+from starlette.requests import Request
+from starlette.responses import JSONResponse, Response
+
+import redis.asyncio as redis
+from redis.asyncio.connection import ConnectionPool
 
 app = FastAPI()