pgAdmin 4 commit: Update dependencies in the Docker container and remov

Update dependencies in the Docker container and remove PG 9.4 utilities from the Docker container as it's now out of
support.

Fixes #5552.
Fixes #5553.

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=83cb01b8cde3e7dfad33e49dbcb53d772d44c48f

Modified Files
--------------
Dockerfile                          | 16 +++++-----------
docs/en_US/container_deployment.rst |  1 -
docs/en_US/release_notes_4_22.rst   |  2 ++
3 files changed, 7 insertions(+), 12 deletions(-)