Add pyyaml dependency (#77)

Author: peitili

Pipfile

@@ -1,12 +1,11 @@
 [[source]]
-
 url = "https://pypi.python.org/simple"
 verify_ssl = true
 name = "pypi"
 
 [packages]
-
 boto3 = "*"
 paramiko = "*"
 requests = "*"
 urllib3 = ">=1.24.2"
+pyyaml = "*"