Run CI tests on 3.14

[amyreese]

Summary

Adds 3.14 to the CI matrix

Test Plan

Look at CI results

[zsol]

Looks like the tests are failing

[ngoldbaum]

I can't reproduce the crash on the Mac build but I do see the failure the other runners also saw.

The exception comes from here:

LibCST/libcst/codegen/gen_matcher_classes.py

Lines 394 to 400 in be0b668

	# Now, convert the type to allow for MetadataMatchType and MatchIfTrue values.
	if isinstance(typecst, cst.Subscript):
	clean_type = _get_clean_type_from_subscript(aliases, typecst)
	elif isinstance(typecst, (cst.Name, cst.SimpleString)):
	clean_type = _get_clean_type_from_expression(aliases, typecst)
	else:
	raise Exception("Logic error, unexpected top level type!")

If I modify that error to tell me about the type that's getting passed in, I get

Exception: Logic error, unexpected top level type! Found BinaryOperation(
    left=SimpleString(
        value="'BaseExpression'",
        lpar=[],
        rpar=[],
    ),
    operator=BitOr(
        whitespace_before=SimpleWhitespace(
            value=' ',
        ),
        whitespace_after=SimpleWhitespace(
            value=' ',
        ),
    ),
    right=Name(
        value='None',
        lpar=[],
        rpar=[],
    ),
    lpar=[],
    rpar=[],
) with type <class 'libcst._nodes.expression.BinaryOperation'>

In a debugger, going up the call stack, it's dying trying to parse the type string 'libcst._nodes.expression.BaseExpression | None'.

I don't know enough about libcst to have any idea why this only happens on 3.14.