fix: signedURL cname (#210)

[kevinnorris]

Fixes #210

• Tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

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[kevinnorris]

I signed it!

[googlebot]

CLAs look good, thanks!

[codecov]

Codecov Report

Merging #234 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #234   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           7      7           
  Lines        1122   1122           
=====================================
  Hits         1122   1122

Impacted Files	Coverage Δ
src/file.js	100% <ø> (ø)	⬆️

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[stephenplusplus]

Awesome, thank you!