Upgrade golangci-lint to v1.19.1

[ferhatelmas]

Nothing serious, internal cleanup but some dep upgrades.

[codecov-io]

Codecov Report

Merging #349 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #349   +/-   ##
=======================================
  Coverage   56.78%   56.78%           
=======================================
  Files          19       19           
  Lines         907      907           
=======================================
  Hits          515      515           
  Misses        339      339           
  Partials       53       53

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[corneliusweig]

Other projects seem to have trouble with excessive memory usage in this version. But I think krew is small enough so that it doesn't matter :)
Thanks for contributing this!
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: corneliusweig, ferhatelmas

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