Use an async decorator for ttl cache in iam provider

The cached decorator from cachetools can't be used on
an async method as the cache returns an awaited
coroutine which can't be awaited again.

coredis/recipes/credentials/iam_provider.py

@@ -7,8 +7,9 @@
 # as coredis[recipes]
 import aiobotocore.session
 from aiobotocore.signers import AioRequestSigner
+from asyncache import cached
 from botocore.model import ServiceId
-from cachetools import TTLCache, cached
+from cachetools import TTLCache
 
 from coredis.credentials import AbstractCredentialProvider, UserPass
 

pyproject.toml

@@ -29,6 +29,7 @@ warn_unused_ignores = true
 module = [
     "async_timeout",
     "beartype",
+    "asyncache",
     "aiobotocore.*",
     "botocore.*",
     "cachetools",

requirements/recipes.txt

@@ -1,3 +1,3 @@
-aiobotocore
-cachetools
+aiobotocore>=2.15.2
+asyncache>=0.3.1