v7.0.0

This release welcomes @TimothyGu to the team! He's been doing phenomenal work, including most of the following:

Adds support for record<>, sequence<>, Promise<>, and FrozenArray<> types.

Adds better error messages for failed conversions.

Removes a leftover special-case that prevented conversion of Dates and RegExps to dictionary types.

Properly throws a TypeError when a value does not match the appropriate interface type; previously interface types were not type-checked.

Fixes the dictionary conversion to properly treat function objects as objects.

Updates iterators so that the iterable impl class will receive unwrapped impls for the key/value, instead of having to do unwrapping itself.

Makes it clear that non-pair iterators are not supported yet, instead of attempting to generate pair-iterator code for them.

Makes all symbol properties non-writable and non-enumerable (but configurable). This hides the impl symbol from Node.js's util.inspect() function, and better matches the specification for @@toStringTag and @@unscopables.

Applies some minimal formatting to the output using prettier.