Network error catching refactor #43

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/urllib3/connectionpool.py", line 588, in urlopen
    conn = self._get_conn(timeout=pool_timeout)
  File "/usr/local/lib/python3.7/site-packages/urllib3/connectionpool.py", line 248, in _get_conn
    return conn or self._new_conn()
  File "/usr/local/lib/python3.7/site-packages/urllib3/connectionpool.py", line 826, in _new_conn
    raise SSLError("Can't connect to HTTPS URL because the SSL "
urllib3.exceptions.SSLError: Can't connect to HTTPS URL because the SSL module is not available.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/requests/adapters.py", line 449, in send
    timeout=timeout
  File "/usr/local/lib/python3.7/site-packages/urllib3/connectionpool.py", line 638, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/local/lib/python3.7/site-packages/urllib3/util/retry.py", line 398, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='api.github.com', port=443): Max retries exceeded with url: /repos/nebbles/gitcommit/tags (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available."))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/bin/gitcommit", line 10, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.7/site-packages/gitcommit/gitcommit.py", line 396, in main
    run()
  File "/usr/local/lib/python3.7/site-packages/gitcommit/gitcommit.py", line 391, in run
    check_for_update()
  File "/usr/local/lib/python3.7/site-packages/gitcommit/updater.py", line 37, in check_for_update
    tags = get_github_tags()
  File "/usr/local/lib/python3.7/site-packages/gitcommit/updater.py", line 12, in get_github_tags
    resp = requests.get("https://api.github.com/repos/nebbles/gitcommit/tags")
  File "/usr/local/lib/python3.7/site-packages/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/requests/api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/requests/sessions.py", line 533, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python3.7/site-packages/requests/sessions.py", line 646, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/requests/adapters.py", line 514, in send
    raise SSLError(e, request=request)
requests.exceptions.SSLError: HTTPSConnectionPool(host='api.github.com', port=443): Max retries exceeded with url: /repos/nebbles/gitcommit/tags (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available."))