Set supported engine to v12.0.0 or higher

Author: christiand93

package-lock.json

@@ -18,7 +18,7 @@
   "homepage": "https://sap.github.io/cf-nodejs-logging-support/",
   "main": "./index.js",
   "engines": {
-    "node": ">=8.0.0"
+    "node": ">=12.0.0"
   },
   "dependencies": {
     "json-stringify-safe": "^5.0.1",