fix: Fix node version by updating to newer docker docker-image. Deprecates armv7 images.

Node 16+ is not available in the alpine image which the previously used docker-image is based on. In order to keep things updated, I have moved to 20.10.10, which DOES provide support for newer Node version, but at the cost of dropping support for armv7.

Sorry to all Raspbery Pi 3- users. Maybe getting a Raspberry Pi 4, which supports arm64, is worth adding to your to-do.