Bump typescript in /samples/request-reply-typescript-greeter

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 3.8.3 to 3.9.2.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](microsoft/TypeScript@v3.8.3...v3.9.2)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

samples/request-reply-typescript-greeter/package-lock.json

@@ -12,6 +12,6 @@
   "author": "Scott Andrews",
   "license": "Apache-2.0",
   "dependencies": {
-    "typescript": "^3.8.3"
+    "typescript": "^3.9.2"
   }
 }