Upgrade sslyze to 3.x

[danielnaab]

To pick up Python 3.8 compatibility, sslyze 3.x is required. Currently, there is an incompatibility:

[pshtt] Scanner not found, or had an error during loading.
	ERROR: <class 'ModuleNotFoundError'>
	No module named 'sslyze.server_connectivity_tester'
Traceback (most recent call last):
  File "/Users/dan/src/10x/domain-scan/utils/scan_utils.py", line 563, in build_scanner_list
    scan = importlib.import_module(
  File "/Users/dan/virtual_envs/domain-scan/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)