Add support for LB with DNS hostname only

[fl42]

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [X] I have read the CONTRIBUTING document.
• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [X] All new and existing tests passed.

AWS Load Balancer (NLB) now uses DNS-based hostname. This PR adds support to extract hostname from Kubernetes Service.

[codecov-commenter]

Codecov Report

Merging #230 (65f7354) into master (7066a84) will decrease coverage by 0.14%. The diff coverage is 40.00%.

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@@            Coverage Diff             @@
##           master     #230      +/-   ##
==========================================
- Coverage   71.57%   71.43%   -0.14%     
==========================================
  Files          24       24              
  Lines        1780     1782       +2     
==========================================
- Hits         1274     1273       -1     
- Misses        406      407       +1     
- Partials      100      102       +2     

Impacted Files	Coverage Δ
internal/k8s/service.go	70.00% <40.00%> (-6.32%)	:arrow_down:

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[utkuozdemir]

Thanks for the PR. Looks good to me. Can you please fix the linter errors? You can use task fmt and task lint for that (you'll need this).

[fl42]

Thanks, fixed :+1:

[fl42]

Sorry, I did the quick fix using online IDE ;)

[utkuozdemir]

Thanks for the contribution :)