Support for deprecating global members produced by enum.EnumMeta._convert_

The ssl module is currently removing a number of deprecated module global enum flags

when a module global is deprecated a module level __getattr__ is used to raise a DeprecationWarning eg

However this wasn’t done for ssl because this is not ergonomic when using enum.EnumMeta._convert_ as the only workaround is ugly: using del to delete the global and add it back as deprecated

And so it’s now difficult to know as a downstream consumer of ssl if my project accesses these flags even if it doesn’t pass them to ssl.SSLContext