update requirements and README

tests/letstest/README.md

@@ -19,8 +19,8 @@ These tests require Python 2.7, awscli, boto3, PyYAML, and fabric<2.0. If you
 have Python 2.7 and virtualenv installed, you can use requirements.txt to
 create a virtual environment with a known set of dependencies by running:
 ```
-virtualenv --python $(command -v python2.7 || command -v python2 || command -v python) venv
-. ./venv/bin/activate
+python3 -m venv venv3
+. ./venv3/bin/activate
 pip install --requirement requirements.txt
 ```
 

tests/letstest/multitester.py

@@ -443,7 +443,7 @@ def main():
 
     # Set up EC2 instances
     #-------------------------------------------------------------------------------
-    configdata = yaml.load(open(cl_args.config_file, 'r'))
+    configdata = yaml.safe_load(open(cl_args.config_file, 'r'))
     targetlist = configdata['targets']
     print('Testing against these images: [%d total]'%len(targetlist))
     for target in targetlist:

tests/letstest/requirements.txt

@@ -5,9 +5,9 @@ cffi==1.14.0
 cryptography==2.8
 docutils==0.15.2
 enum34==1.1.9
-Fabric==1.14.1
-futures==3.3.0
+Fabric==2.5.0
 ipaddress==1.0.23
+Invoke==1.4.1
 jmespath==0.9.5
 paramiko==2.7.1
 pycparser==2.19