**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
quota_retry = {
            'stop_after_delay': 2,
            'multiplier': 1,
            'min': 1,
            'max': 10,
        }
        custom_fn = ThrowErrorUntilCount(
            count=2,
            quota_retry=quota_retry,
        )
        with pytest.raises(Exception):
            _non_retryable_test(custom_fn)
    def test_raise_exception_when_no_retry_args(self):
        custom_fn = ThrowErrorUntilCount(count=2, quota_retry=None)
        with pytest.raises(Exception):
            _retryable_test(custom_fn)