Update Alpine Linux version in the docker container. This also updates the PG utilities to v11. Fixes #3991

docs/en_US/release_notes_4_3.rst

@@ -11,6 +11,7 @@ Features
 
 | `Feature #1825 <https://redmine.postgresql.org/issues/1825>`_ - Install a script to start pgAdmin (pgadmin4) from the command line when installed from the Python wheel.
 | `Feature #3439 <https://redmine.postgresql.org/issues/3439>`_ - Allow X-FRAME-OPTIONS to be set for security. Default to SAMEORIGIN.
+| `Feature #3991 <https://redmine.postgresql.org/issues/3991>`_ - Update Alpine Linux version in the docker container. This also updates the PG utilities to v11.
 
 Bug fixes
 *********

pkg/docker/Dockerfile

@@ -19,7 +19,7 @@ RUN yarn install --cache-folder ./ycache --verbose && \
     rm -rf ./ycache ./pgadmin/static/js/generated/.cache
 
 # Build Sphinx documentation in separate container
-FROM python:3.6-alpine3.7 as docs-builder
+FROM python:3.7-alpine3.9 as docs-builder
 
 # Install only dependencies absolutely required for documentation building
 RUN apk add --no-cache make
@@ -32,8 +32,7 @@ COPY ./pgadmin4/ /pgadmin4
 RUN LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8 make -C /pgadmin4/docs/en_US -f Makefile.sphinx html
 
 # Then install backend, copy static files and set up entrypoint
-# Need alpine3.7 to get pg_dump and friends in postgresql-client package
-FROM python:3.6-alpine3.7
+FROM python:3.7-alpine3.9
 
 RUN pip --no-cache-dir install gunicorn
 RUN apk add --no-cache postfix postgresql-client postgresql-libs