fix: project/c2-microservices-v1/udacity-c2-restapi-user/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133
- https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133
- https://snyk.io/vuln/SNYK-UPSTREAM-NODE-3092933
- https://snyk.io/vuln/SNYK-DEBIAN11-KRB5-7411316
- https://snyk.io/vuln/SNYK-DEBIAN11-KRB5-7411316

Author: snyk-bot

project/c2-microservices-v1/udacity-c2-restapi-user/Dockerfile

@@ -1,5 +1,5 @@
 # Set the base image
-FROM node:18.9.1-slim
+FROM node:18.20.3-slim
 # Create app directory
 WORKDIR /usr/src/app
 # Copy package.json AND package-lock.json