Release patch version of Reffy - v18.6.3

Code changes:
- Remove mocha dependency for test suite (#1837)

Dependencies bumped:
- Bump rollup from 4.40.2 to 4.41.0 (#1836)
- Bump respec from 35.3.1 to 35.4.0 (#1833)
- Bump commander from 13.1.0 to 14.0.0 (#1835)
- Bump undici from 7.9.0 to 7.10.0 (#1838)
- Bump puppeteer from 24.8.2 to 24.9.0 (#1839)
- Bump web-specs from 3.50.0 to 3.51.0 (#1840)

Author: tidoust

package.json

@@ -1,6 +1,6 @@
 {
   "name": "reffy",
-  "version": "18.6.2",
+  "version": "18.6.3",
   "description": "W3C/WHATWG spec dependencies exploration companion. Features a short set of tools to study spec references as well as WebIDL term definitions and references found in W3C specifications.",
   "repository": {
     "type": "git",