Deprecation warnings in Python 3.10

[mikemanger]

Running the tests in Python 3.10 and upwards gives the following deprecation warnings:

\createsend-python\lib\createsend\utils.py:106: DeprecationWarning: ssl.SSLContext() without protocol argument is deprecated.
    context = ssl.SSLContext()

\createsend-python\lib\createsend\utils.py:106: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
    context = ssl.SSLContext()

There is some documentation here:

• ssl.SSLContext()
• ssl.PROTOCOL_TLS

It should be safe to update this method for all supported versions of Python.