Install script doesn't work with the new version of pyyaml (5.1)

[ericgoode]

Receive the following error:

Traceback (most recent call last): File "./bin/prepare-config.py", line 90, in loaded = yaml.safe_load(open(args.input_file, "r")) File "/usr/local/lib/python3.7/site-packages/yaml/init.py", line 94, in safe_load return load(stream, SafeLoader) File "/usr/local/lib/python3.7/site-packages/yaml/init.py", line 72, in load return loader.get_single_data() File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 37, in get_single_data return self.construct_document(node) File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 46, in construct_document for dummy in generator: File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 393, in construct_yaml_seq data.extend(self.construct_sequence(node)) File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 116, in construct_sequence for child in node.value] File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 116, in for child in node.value] File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 86, in construct_object data = constructor(self, node) File "/usr/local/lib/python3.7/site-packages/yaml/constructor.py", line 414, in construct_undefined node.start_mark) yaml.constructor.ConstructorError: could not determine a constructor for the tag '!include' in "marathon/demo.yml", line 3, column 5