Support for SLDS styling hooks

[nathanlb]

Describe the bug
The use of styling hooks , particularly when defining them, does not appear to be supported by the lwc-dev-server. Using them in a component's css will crash the component's initialization. The SLDS team has suggested that it would be due to the dev server using an older version of the SLDS.
We've adopted the lwc-dev-server in our development and love it so much that we have a hard time giving it up. As a result, we're having to find roundabout ways to solve problems that can easily be solved with the styling hooks since they are not supported.

To Reproduce
Steps to reproduce the behavior:

1. Set value on styling hooks in a component's css file
2. Attempt to preview it in the lwc-dev-server

Expected behavior
The use of styling hooks to be supported by lwc-dev-server.

Screenshots
**/lwc/component/component.css

:host {
    --sds-c-card-sizing-border: 1px;
}

Desktop (please complete the following information):

Issue not specific to this setup.

• OS: MacOS
• Browser Chrome
• Version 93.0.4577.63 (Official Build) (x86_64)

[stale]

This issue has been automatically marked as type:bug-p3 because it has not had recent activity.