**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.
airflow/providers/amazon/aws/hooks/base_aws.py
conf_format = config_format.lower()
    if conf_format == "boto":  
        if profile is not None and "profile " + profile in sections:
            cred_section = "profile " + profile
        else:
            cred_section = "Credentials"
    elif conf_format == "aws" and profile is not None:
        cred_section = profile
    else:
        cred_section = "default"
    
    if conf_format in ("boto", "aws"):  
        key_id_option = "aws_access_key_id"
        secret_key_option = "aws_secret_access_key"
        
    else:
        key_id_option = "access_key"
        secret_key_option = "secret_key"
    
    if cred_section not in sections:
        raise AirflowException("This config file format is not recognized")
    else:
        try:
            access_key = config.get(cred_section, key_id_option)
            secret_key = config.get(cred_section, secret_key_option)
        except Exception:
            logging.warning("Option Error in parsing s3 config file")
            raise
        return access_key, secret_key