Timezone resets to UTC when removing tzdata as per wiki

I'm using `node:10.1-alpine`.

Following the steps from this Wiki page to setup the OS timezone: https://wiki.alpinelinux.org/wiki/Setting_the_timezone

I'm noticing that the system timezone gets reset to UTC if I cleanup and delete the tzdata package once I'm done setting up and confirming the correct timezone.

Not sure if the last step in that wiki needs to be removed or if I did something incorrectly to maintain the timezone preference?

Will result in image with UTC:
`RUN apk add --update tzdata && cp /usr/share/zoneinfo/America/New_York /etc/localtime && echo "America/New_York" > /etc/timezone && apk del tzdata && rm -rf /var/cache/apk/* && rm -rf /usr/local/share/.cache`

Will result in image with EDT:
`RUN apk add --update tzdata && cp /usr/share/zoneinfo/America/New_York /etc/localtime && echo "America/New_York" > /etc/timezone && rm -rf /var/cache/apk/* && rm -rf /usr/local/share/.cache`