BUG #15470: Docker image dpage/pgadmin4:3.4 (and latest) fail with non-root user

The following bug has been logged on the website:

Bug reference: 15470
Logged by: Daniel Dan
Email address: lms22114(at)awsoo(dot)com
PostgreSQL version: 11.0
Operating system: Docker Image
Description:

In some productive environments it is not allowed to run Docker containers
with root user (uid 0)

When pgadmin4 container is run with (user adm):
docker run --name pgadmin -u 3:4 -e
PGADMIN_DEFAULT_EMAIL=pgadmin(at)example(dot)com -e PGADMIN_DEFAULT_PASSWORD=admin
dpage/pgadmin4:latest

The following errors occur:
Traceback (most recent call last):
File "run_pgadmin.py", line 4, in <module>
from pgAdmin4 import app
File "/pgadmin4/pgAdmin4.py", line 70, in <module>
app = create_app()
File "/pgadmin4/pgadmin/__init__.py", line 225, in create_app
create_app_data_directory(config)
File "/pgadmin4/pgadmin/setup/data_directory.py", line 26, in
create_app_data_directory
_create_directory_if_not_exists(os.path.dirname(config.LOG_FILE))
File "/pgadmin4/pgadmin/setup/data_directory.py", line 15, in
_create_directory_if_not_exists
os.mkdir(_path)
PermissionError: [Errno 13] Permission denied: '/var/log/pgadmin'
[2018-10-30 06:33:20 +0000] [1] [INFO] Starting gunicorn 19.8.1
[2018-10-30 06:33:20 +0000] [1] [ERROR] Retrying in 1 second.
[2018-10-30 06:33:21 +0000] [1] [ERROR] Retrying in 1 second.
[2018-10-30 06:33:22 +0000] [1] [ERROR] Retrying in 1 second.
[2018-10-30 06:33:23 +0000] [1] [ERROR] Retrying in 1 second.
[2018-10-30 06:33:24 +0000] [1] [ERROR] Retrying in 1 second.
[2018-10-30 06:33:25 +0000] [1] [ERROR] Can't connect to ('::', 80)