feat: fix force-update for zero-replica deployments by reading image tags from spec

[chansuke]

trafficstars

Closes #829

Resolves continuous update attempts for deployments with 0 replicas when force-update=true is set

[codecov-commenter]

Codecov Report

:x: Patch coverage is 51.72414% with 56 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 70.40%. Comparing base (2ba14b5) to head (54fc293).

Files with missing lines	Patch %	Lines
pkg/argocd/argocd.go	59.34%	34 Missing and 3 partials :warning:
pkg/argocd/update.go	24.00%	18 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1172      +/-   ##
==========================================
- Coverage   70.85%   70.40%   -0.46%     
==========================================
  Files          45       45              
  Lines        5178     5288     +110     
==========================================
+ Hits         3669     3723      +54     
- Misses       1344     1396      +52     
- Partials      165      169       +4     

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[chengfang]

@chansuke can you investigate the CI failures?

[chansuke]

@chengfang yes:+1: