func NewSessionTokenProvider(cfg aws.Config) *SessionTokenProvider {
	b := newBaseStsProvider(cfg)
	b.Duration = SessionTokenDurationDefault
	b.ExpiryWindow = -1
	return &SessionTokenProvider{b}
}
NewSessionTokenProvider configures a default SessionTokenProvider to allow retrieval of Session Token credentials.
The default provider uses the specified client.ConfigProvider to create a new sts.STS client. The credential duration
is set to SessionTokenDurationDefault, and the ExpiryWindow is set to 10% of the duration value.
package credentials
import (
	"context"
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/sts"
	"time"
)
const (
	SessionTokenProviderName = "SessionTokenProvider"
	SessionTokenDurationMin = 15 * time.Minute
	SessionTokenDurationMax = 36 * time.Hour
	SessionTokenDurationDefault = 12 * time.Hour
)
type SessionTokenProvider struct {
	*baseStsProvider
}