Update base/phantom_s3_bucket/README.md

Co-authored-by: Colby Williams <colby.williams@accenturefederal.com>

base/phantom_s3_bucket/README.md

@@ -1,6 +1,6 @@
 # Creates an S3 bucket and role for phantom
 
-Phantom instnace must assume-role first. To do this from the command-line:
+Phantom instance must assume-role first. To do this from the command-line:
 
 ```
 aws --region us-gov-east-1 sts assume-role --role-arn arn:aws-us-gov:iam::738800754746:role/service/phantom_s3 --role-session-name ftd_testing