Fix with-docker example dockerfile (#33695)

Fixed `dockerfile` in `with-docker`  example

## Bug

- error when executing `docker build -t nextjs-docker .` - `yarn.lock` file is missing

 ## Documentation / Examples

- edited to not fail when `package-lock.json` or `yarn.lock` are not found
- example: use `with-docker` example

- [x] Make sure the linting passes by running yarn lint

Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>

examples/with-docker/Dockerfile

@@ -6,6 +6,10 @@ WORKDIR /app
 COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile
 
+# If using npm with a `package-lock.json` comment out above and use below instead
+# COPY package.json package-lock.json / 
+# RUN npm install
+
 # Rebuild the source code only when needed
 FROM node:16-alpine AS builder
 WORKDIR /app