Fix warning

Author: jcreedcmu

extensions/ql-vscode/gulpfile.ts/tsconfig.json

@@ -8,7 +8,7 @@
     "lib": ["es6"],
     "moduleResolution": "node",
     "sourceMap": true,
-    "rootDir": "src",
+    "rootDir": ".",
     "strictNullChecks": true,
     "noFallthroughCasesInSwitch": true,
     "preserveWatchOutput": true,