Write Permissions on .cache in httplib2

[johndavis23]

I'm seeing this failure:

eventList = events(url=tier1A, file=None, start=today, end=one_year_from_now)
File "/var/task/icalevents/icalevents.py", line 38, in events
ical_download = ICalDownload(http=http)
File "/var/task/icalevents/icaldownload.py", line 37, in init
http = Http('.cache')
File "/var/task/httplib2/init.py", line 1461, in init
self.cache = FileCache(cache)
File "/var/task/httplib2/init.py", line 925, in init
os.makedirs(self.cache)
File "/var/lang/lib/python3.7/os.py", line 221, in makedirs
mkdir(name, mode)
OSError: [Errno 30] Read-only file system: '.cache'

Which I take it was meant to be resolved via #52

I'm running 0.1.24 via serverless framework on aws lambda.

[Hultner]

Resolved in #72