Use CRT for cloudfront url signing

Author: kdaily

awscli/customizations/cloudfront.py

@@ -15,6 +15,9 @@
 import sys
 import time
 
+from botocore.signers import CloudFrontSigner
+from botocore.utils import parse_to_aware_datetime
+
 from awscrt.crypto import RSA, RSASignatureAlgorithm
 
 from awscli.arguments import CustomArgument