[OSX] missing ~/.aws folder prevents cca init running

[sandfox]

If there is no ~/.aws folder, cca init can't run.

After installing cca on a new machine and then running cca init <token> it then fails with the following:

INI file: /Users/sandfox/.aws/credentials does not exist
Traceback (most recent call last):
  File "/Users/sandfox/Library/Python/3.8/lib/python/site-packages/cca/cca.py", line 35, in <module>
    config = IniFile(os.path.expanduser(configfn), takebackup=False)
  File "/Users/sandfox/Library/Python/3.8/lib/python/site-packages/cca/cliinifile.py", line 52, in __init__
    raise FileExistsError("INI file: {} does not exist".format(self.filename))
FileExistsError: INI file: /Users/sandfox/.aws/credentials does not exist

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/sandfox/Library/Python/3.7/bin/cca", line 6, in <module>
    from cca.cca import cca
  File "/Users/sandfox/Library/Python/3.8/lib/python/site-packages/cca/cca.py", line 49, in <module>
    open(os.path.expanduser(configfn), "a").close()
FileNotFoundError: [Errno 2] No such file or directory: '/Users/sandfox/.aws/credentials'

creating the folder ~/.aws allows the command to complete.