chore(deps): update rspack and swc helpers to latest versions

- Upgraded @rspack/cli and @rspack/core from 1.6.7 to 1.6.8.
- Updated @swc/helpers from 0.5.17 to 0.5.18.
- Adjusted corresponding entries in pnpm-lock.yaml to reflect these changes.

Author: jackiotyu

package.json

@@ -1177,9 +1177,9 @@
     "check-types": "tsc --noEmit"
   },
   "devDependencies": {
-    "@rspack/cli": "^1.6.7",
-    "@rspack/core": "^1.6.7",
-    "@swc/helpers": "^0.5.17",
+    "@rspack/cli": "^1.6.8",
+    "@rspack/core": "^1.6.8",
+    "@swc/helpers": "^0.5.18",
     "@types/lodash-es": "^4.17.12",
     "@types/mocha": "^10.0.10",
     "@types/node": "16.x",