Support TLS 1.3 on Apple platforms

[jbelkins]

Describe the feature

Support for TLS 1.3 on Apple

Use Case

Support for TLS 1.3

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

[waahm7]

TODO: Verify S2N can do TLS 1.3 as well.