Bump through2 from 3.0.2 to 4.0.2 in /extensions/ql-vscode

Bumps [through2](https://github.com/rvagg/through2) from 3.0.2 to 4.0.2.
- [Release notes](https://github.com/rvagg/through2/releases)
- [Commits](rvagg/through2@v3.0.2...v4.0.2)

---
updated-dependencies:
- dependency-name: through2
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

extensions/ql-vscode/package-lock.json

@@ -1175,7 +1175,7 @@
     "sinon": "~9.0.0",
     "sinon-chai": "~3.5.0",
     "style-loader": "~0.23.1",
-    "through2": "^3.0.1",
+    "through2": "^4.0.2",
     "ts-loader": "^8.1.0",
     "ts-node": "^8.3.0",
     "ts-protoc-gen": "^0.9.0",