fix: uid instead of named user (fixes #2746)

[t-v]

When specifying:

containerSecurityContext:
  runAsNonRoot: true
  capabilities:
    drop:
      - all

You keep getting the error:

    state:
      waiting:
        message: container has runAsNonRoot and image has non-numeric user (argocd),
          cannot verify user is non-root
        reason: CreateContainerConfigError

And since we are creating user 999 inside the container, it is better to use this user by UID than by username.

issue: #2746

Checklist:

• this is a bug fix
• The title of the PR states what changed and the related issues number (used for the release note).
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Optional. My organization is added to the README.
• I've signed the CLA and my build is green (troubleshooting builds).

[codecov]

Codecov Report

Merging #3108 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #3108   +/-   ##
======================================
  Coverage    38.6%   38.6%           
======================================
  Files         168     168           
  Lines       18269   18269           
  Branches      237     237           
======================================
  Hits         7053    7053           
  Misses      10342   10342           
  Partials      874     874

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[jannfis]

Hm, I'm wondering - would specifying runAsUser and runAsGroup in the pod's security context have the same effect?

[t-v]

it would, but wouldn't it be better support runAsNonRoot by default?
I currently run it with the runAsUser and runAsGroup option, so it works, but I think if it would be cleaner if you didn't need to specify it.

[CLAassistant]

All committers have signed the CLA.

[jannfis]

LGTM - Thank you for your submission and I'm very sorry for the long delay @t-v

@alexmt Do you have any objections to this change?

[alex1989hu]

I would be happy to see it merged (also met this error message). Do you need any assistance?

[jannfis]

Slipped through - sorry. Merging now :)