Use Ubuntu base image in Dockerfile, because according to Quay.io security scan it does not have any vulnerabilities, that node base images do have.

Thanks to xet7 !

Fixes #2762,
fixes https://github.com/wekan/wekan/pull/3438

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:12 AS builder
+FROM quay.io/wekan/ubuntu:groovy-20201125.2 AS builder
 # This is our builder image. It will take the Wekan meteor code and
 # build it into a standalone NodeJS package
 
@@ -36,7 +36,7 @@ RUN cd /build/bundle/programs/server/ && \
 RUN rm -rf /build/bundle/programs/web.browser.legacy
 
 
-FROM node:12-slim as app
+FROM quay.io/wekan/ubuntu:groovy-20201125.2 as app
 # This is our runtime image. It takes the built NodeJS package and runs it using
 # the lighter Alpine NodeJS base image to keep image size down