chore(deps): update node.js to v12.20.0 (#2085)

Co-authored-by: F. Hinkelmann <[email protected]>

Author: renovate-bot

appengine/hello-world/flexible/package.json

@@ -10,7 +10,7 @@
     "url": "https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git"
   },
   "engines": {
-    "node": "12.19.1"
+    "node": "12.20.0"
   },
   "scripts": {
     "start": "node app.js",

appengine/storage/flexible/package.json

@@ -6,7 +6,7 @@
     "test": "mocha system-test/*.test.js --exit --timeout=30000"
   },
   "engines": {
-    "node": "12.19.1"
+    "node": "12.20.0"
   },
   "dependencies": {
     "@google-cloud/storage": "^5.3.0",