Bump to go1.18.1 and fix linter errors

[enj]

Signed-off-by: Monis Khan mok@vmware.com

Release note:

Pinniped components are now compiled with Go 1.18.1.

[codecov]

Codecov Report

Merging #1118 (63076a6) into main (d0d20e0) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1118   +/-   ##
=======================================
  Coverage   79.73%   79.73%           
=======================================
  Files         136      136           
  Lines       10055    10055           
=======================================
  Hits         8017     8017           
  Misses       1767     1767           
  Partials      271      271           

Impacted Files	Coverage Δ
cmd/pinniped/cmd/kubeconfig.go	84.18% <100.00%> (ø)

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