fix: URL.String() data race panic

[georgehao]

What this PR does:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-io]

Codecov Report

Merging #944 (5683e9f) into develop (ce90b4b) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #944      +/-   ##
===========================================
+ Coverage    60.19%   60.24%   +0.05%     
===========================================
  Files          260      260              
  Lines        12884    12886       +2     
===========================================
+ Hits          7755     7763       +8     
+ Misses        4172     4166       -6     
  Partials       957      957              

Impacted Files	Coverage Δ
common/url.go	59.62% <100.00%> (+0.25%)	⬆️
cluster/router/chain/chain.go	68.54% <0.00%> (-1.62%)	⬇️
remoting/getty/listener.go	41.62% <0.00%> (+0.54%)	⬆️
remoting/getty/pool.go	71.36% <0.00%> (+1.76%)	⬆️
remoting/kubernetes/listener.go	53.68% <0.00%> (+3.15%)	⬆️

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[cityiron]

By the way, I found this class import cm "github.com/Workiva/go-datastructures/common" is in first package part, you can move to second.