chore: display node version during 'build' command

Author: padamstx

package.json

@@ -17,7 +17,7 @@
     "tslint:check": "tslint -p . -c ./tslint.json",
     "lint": "npm run eslint:check && npm run tslint:check",
     "lint-fix": "npm run eslint:fix && npm run tslint:fix",
-    "build": "tsc && cp package.json dist/ && npm list ibm-cloud-sdk-core",
+    "build": "tsc && cp package.json dist/ && npm list ibm-cloud-sdk-core && node --version",
     "prepublishOnly": "npm run build",
     "postversion": "tsc-publish --no-checks --dry-run",
     "jest": "jest",