Use GitHub release zip for WebAuthn provider, drop explicit core ref

The WebAuthn provider GitHub source needs composer install, so use the
pre-built release zip from GitHub instead. Remove the explicit WordPress
core ref — wp-env's default core download is much faster than cloning
WordPress/WordPress with all its branches.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: obenland

.wp-env.json

@@ -1,11 +1,10 @@
 {
-	"core": "WordPress/WordPress",
 	"multisite": true,
 	"plugins": [
 		"WordPress/gutenberg",
 		"bbpress/bbPress",
 		"WordPress/two-factor",
-		"https://downloads.wordpress.org/plugin/two-factor-provider-webauthn.latest-stable.zip",
+		"https://github.com/sjinks/wp-two-factor-provider-webauthn/releases/latest/download/two-factor-provider-webauthn.zip",
 		"."
 	],
 	"mappings": {