message: Updating alpine Docker.build to v3.13
diff: #-----------------BUILDER-----------------
  #-----------------------------------------
  -FROM node:14-alpine3.11 AS builder
  +FROM node:14-alpine3.13 AS builder
  RUN apk add --update-cache --repository https://alpine.global.ssl.fastly.net/alpine/v3.11/community/ \
  python build-base sqlite-dev sqlite-libs vips-dev fftw-dev gcc g++ make libc6-compat
  COPY pigallery2-release /app
  @@ -14,7 +14,7 @@ RUN mkdir -p /app/data/config && \
  #-----------------MAIN--------------------
  #-----------------------------------------
  -FROM node:14-alpine3.11 AS main
  +FROM node:14-alpine3.13 AS main
  WORKDIR /app
  ENV NODE_ENV=production \
  # overrides only the default value of the settings (the actualy value can be overwritten through config.json)
  