**Apache Airflow version**: 1.10.8 (Patched with latest AWS Hook)

**Environment**:

- **Cloud provider or hardware configuration**: 4 VCPU 8GB RAM VM
- **OS** (e.g. from /etc/os-release): RHEL 7.7
- **Kernel** (e.g. `uname -a`): Linux 3.10.0-957.el7.x86_64
- **Install tools**:
- **Others**:
The AWS Hook functionality for AssumeRoleWithSAML is not available in this version, we manually added it via patching the hook file.

**What happened**:
We've been using this hook for a while now with this issue, basically sts.assume_role and sts.assume_role_with_saml will return temporary credentials that are only valid for eg 1 hour by default. Eventually with long running operators / hooks / sensors some of them fail because the credentials have expired.

Example error messages
An error occurred (ExpiredTokenException) when calling the AssumeRole operation: Response has expired
An error occurred (ExpiredTokenException) when calling the AssumeRoleWithSAML operation: Response has expired
botocore.exceptions.ClientError: An error occurred (ExpiredTokenException) when calling the <any operation here> operation: The security token included in the request is expired

**What you expected to happen**:

AWS hook should be updated to use boto3 RefreshableCredentials when temporary credentials are in use.

**How to reproduce it**:

Use any of the assume role methods with the AWS Hook, create a session, wait 1 hour (or whatever expiry period applies to your role), and try and use the hook again.

**Anything else we need to know**:

I have a solution, please self-assign this.
tests/providers/amazon/aws/hooks/test_base_aws.py
#
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import json
import unittest
from base64 import b64encode
from unittest import mock
import boto3
import pytest
from moto.core import ACCOUNT_ID
from airflow.models import Connection
from airflow.providers.amazon.aws.hooks.base_aws import AwsBaseHook
try:
    from moto import mock_dynamodb2, mock_emr, mock_iam, mock_sts
except ImportError:
    mock_emr = None
    mock_dynamodb2 = None
    mock_sts = None
    mock_iam = None
SAML_ASSERTION = """
<?xml version="1.0"?>
<samlp:Response xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" ID="_00000000-0000-0000-0000-000000000000" Version="2.0" IssueInstant="2012-01-01T12:00:00.000Z" Destination="https://signin.aws.amazon.com/saml" Consent="urn:oasis:names:tc:SAML:2.0:consent:unspecified">
  <Issuer xmlns="urn:oasis:names:tc:SAML:2.0:assertion">http://localhost/</Issuer>
  <samlp:Status>
    <samlp:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/>