fix version check to work with release candidates

[celenechang]

What does this PR do?

Defaulting was not behaving properly for prelease/release candidate images because of image tag comparison using semver. If -0 is added to the minVersion image being compared then prelease image tags are compared.

Ref: https://github.com/Masterminds/semver#working-with-prerelease-versions

Motivation

Unexpected behavior when testing an agent release candidate

Additional Notes

Anything else we should know when reviewing?

Describe your test plan

Test a datadog agent release candidate image with DatadogAgent in a non-Docker environment. Make sure that the DOCKER_HOST env var is not automatically set in the agent containers and the docker check does not run.

[github-actions]

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[codecov-commenter]

Codecov Report

Merging #336 (7ea885f) into main (9dd611c) will increase coverage by 3.20%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             main     #336      +/-   ##
==========================================
+ Coverage   63.18%   66.39%   +3.20%     
==========================================
  Files          60       60              
  Lines        6609     7204     +595     
==========================================
+ Hits         4176     4783     +607     
+ Misses       2129     2117      -12     
  Partials      304      304              

Flag	Coverage Δ
unittests	66.39% <50.00%> (+3.20%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
controllers/datadogagent/finalizer.go	30.76% <0.00%> (ø)
api/v1alpha1/datadogagent_default.go	82.62% <100.00%> (+3.57%)	⬆️
controllers/datadogagent/utils.go	87.94% <0.00%> (+5.21%)	⬆️
controllers/datadogagent_controller.go	70.45% <0.00%> (+9.84%)	⬆️

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