Python-liquid

- Explicit re-export
- Changed `Context._tag_namespace` to `Context.tag_namespace`.

- Fixed manifest error.

- Test against Python Babel 2.12 which includes CLDR 42.

- Test against Python 3.10 and Django 4.0.

- **Breaking Change**: Both `Environment.fromString()` and `Template.fromString()` have been changed to accept a template source string (as before), render context globals as the second argument, and a `TemplateContext` object as an optional third argument.
- **Breaking Change**: The `children` method of the `Node` interface is now optional. If implemented it should return an array of `ChildNode`s, whereas before it would have been an array of `Nodes`.
- **Breaking Change**: `TemplateParser.parseBlock()` now accepts an optional `token` argument. If given, this token will be assigned to the resulting block. The current token in the stream will be used otherwise. All built-in block tags now pass their initial tag to `parseBlock()` instead of the tag for the first node in the block.

- Moved folder `liquid` to `shopify_liquid`.
- Updated Shopify/Liquid from GitHub main.
- Updated LiquidJS to 10.20.1
- Added Python Liquid2