Bump typescript from 3.8.3 to 3.9.2

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

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

package.json

@@ -48,7 +48,7 @@
         "terser-webpack-plugin": "^3.0.1",
         "tfx-cli": "^0.7.11",
         "ts-loader": "^7.0.4",
-        "typescript": "^3.8.3",
+        "typescript": "^3.9.2",
         "webpack": "^4.43.0",
         "webpack-cli": "^3.3.11"
     }